Organic light-emitting device

ABSTRACT

An organic light-emitting device including a first compound represented by Formula 1 and a second compound represented by one of Formulae 2A to 2C.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to Korean PatentApplication No. 10-2016-0008913, filed on Jan. 25, 2016 in the KoreanIntellectual Property Office, the disclosure of which is incorporated byreference herein in its entirety.

TECHNICAL FIELD

Exemplary embodiments of the present invention relate to alight-emitting device, and more particularly to an organiclight-emitting device.

DISCUSSION OF RELATED ART

Organic light-emitting devices may be self-emission devices. Organiclight-emitting devices may have relatively wide viewing angles,relatively high contrast ratios, and relatively short response times,and increased brightness, driving voltage, and response speedcharacteristics. Organic light-emitting devices may produce full-colorimages.

Organic light-emitting devices may include a first electrode disposed ona substrate. Organic light-emitting devices may include a hole transportregion, an emission layer, an electron transport region, and a secondelectrode sequentially disposed on the first electrode. Holes providedfrom the first electrode may move toward the emission layer through thehole transport region. Electrons provided from the second electrode maymove toward the emission layer through the electron transport region.Carriers, such as holes and electrons, may recombine in the emissionlayer to produce excitons. The excitons may transition from an excitedstate to a ground state, thus generating light.

SUMMARY

One or more exemplary embodiments of the present invention may includean organic light-emitting device including a first and second compound.

According to one or more exemplary embodiments of the present invention,an organic light-emitting device includes:

-   -   a first electrode;    -   a second electrode facing the first electrode; and    -   an organic layer disposed between the first electrode and the        second electrode, the organic layer including an emission layer.

The organic layer includes a first compound represented by Formula 1 anda second compound represented by one of Formulae 2A to 2C:

In Formulae 1 and 2A to 2C:

-   -   X₁ is selected from C(R₄)(R₅) and Si(R₄)(R₅), and R₄ and R₅ are        linked to form a ring,    -   X₂ is selected from O, S, C(Z₂₁)(Z₂₂), N(Z₂₃), and Si(Z₂₄)(Z₂₅),    -   Z₂₁ to Z₂₅ are each independently selected from hydrogen,        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group, a        fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl        group, a dibenzofluorenyl group, a phenanthrenyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a        triazinyl group, —Si(Q₄₁)(Q₄₂)(Q₄₃), —N(Q₄₁)(Q₄₂), —B(Q₄₁)(Q₄₂),        —C(═O)(Q₄₁), —S(═O)₂(Q₄₁), and —P(═O)(Q₄₁)(Q₄₂),    -   L₁, L₁₁, L₁₂, L₂₁ to L₂₃, and L₃₁ to L₃₅ are each independently        selected from a substituted or unsubstituted C₃-C₁₀        cycloalkylene group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀        cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkenylene group, a substituted or unsubstituted        C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀        heteroarylene group, a substituted or unsubstituted divalent        non-aromatic condensed polycyclic group, and a substituted or        unsubstituted divalent non-aromatic condensed heteropolycyclic        group,    -   a1, a11, a12, a21 to a23, and a31 to a35 are each independently        an integer selected from 0 to 5; when a1 is 2 or greater, at        least two L₁(s) are the same as or different from each other;        when a11 is 2 or greater, at least two L₁₁(s) are the same as or        different from each other; when a12 is 2 or greater, at least        two L₁₂(s) are the same as or different from each other; when        a21 is 2 or greater, at least two L₂₁(s) are the same as or        different from each other; when a22 is 2 or greater, at least        two L₂₂(s) are the same as or different from each other; when        a23 is 2 or greater, at least two L₂₃(s) are the same as or        different from each other; when a31 is 2 or greater, at least        two L₃₁(s) are the same as or different from each other; when        a32 is 2 or greater, at least two L₃₂(s) are the same as or        different from each other; when a33 is 2 or greater, at least        two L₃₃(s) are the same as or different from each other; when        a34 is 2 or greater, at least two L₃₄(s) are the same as or        different from each other; and when a35 is 2 or greater, at        least two L₃₅(s) are the same as or different from each other,    -   A₁ is selected from P(═O)(R₄₁)(R₄₂) or S(═O)₂(R₄₃),    -   b1 is an integer selected from 1 to 5; when b1 is 2 or greater,        at least two A₁ (s) are the same as or different from each        other,    -   Ar₁₁ is selected from a substituted or unsubstituted C₃-C₁₀        cycloalkyl group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀        cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀        aryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl        group, a substituted or unsubstituted monovalent non-aromatic        condensed polycyclic group, and a substituted or unsubstituted        monovalent non-aromatic condensed heteropolycyclic group,    -   b11 is an integer selected from 1 to 5; when b11 is 2 or        greater, at least two Ar₁₁(s) are the same as or different from        each other,    -   R₁ to R₅, R₁₁ to R₁₄, R₂₁ to R₂₃, R₃₁ to R₃₄, and R₄₁ to R₄₃ are        each independently selected from hydrogen, deuterium, —F, —Cl,        —Br, —I, a hydroxyl group, a cyano group, a nitro group, a        substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted        or unsubstituted C₂-C₆₀ alkenyl group, a substituted or        unsubstituted C₂-C₆₀ alkynyl group, a substituted or        unsubstituted C₁-C₆₀ alkoxy group, a substituted or        unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or        unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or        unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or        unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or        unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted        C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀        arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl        group, a substituted or unsubstituted monovalent non-aromatic        condensed polycyclic group, a substituted or unsubstituted        monovalent non-aromatic condensed heteropolycyclic group,        —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁),        —S(═O)₂(Q₁), or —P(═O)(Q₁)(Q₂),    -   c1 and c11 to c14 are each independently integers selected from        0 to 4; when c1 is 2 or greater, at least two R₁(s) are the same        as or different from each other; when c11 is 2 or greater, at        least two R₁₁(s) are the same as or different from each other;        when c12 is 2 or greater, at least two R₁₂(s) are the same as or        different from each other; when c13 is 2 or greater, at least        two R₁₃(s) are the same as or different from each other; and        when c14 is 2 or greater, at least two R₁₄(s) are the same as or        different from each other,    -   c2 is selected from 0 to 3; when c2 is 2 or greater, at least        two R₂(s) are the same as or different from each other,    -   c3 is selected from 0 to 2; when c3 is 2 or greater, at least        two R₃(s) are the same as or different from each other,    -   c21 to c23 and c31 to c34 are each independently an integer        selected from 1 to 5; when c21 is 2 or greater, at least two        R₂₁(s) are the same as or different from each other; when c22 is        2 or greater, at least two R₂₂(s) are the same as or different        from each other; when c23 is 2 or greater, at least two R₂₃(s)        are the same as or different from each other; when c31 is 2 or        greater, at least two R₃₁(s) are the same as or different from        each other; when c32 is 2 or greater, at least two R₃₂(s) are        the same as or different from each other; when c33 is 2 or        greater, at least two R₃₃(s) are the same as or different from        each other; and when c34 is 2 or greater, at least two R₃₄(s)        are the same as or different from each other, and    -   at least one of substituents of the substituted C₃-C₁₀        cycloalkylene group, substituted C₁-C₁₀ heterocycloalkylene        group, the substituted C₃-C₁₀ cycloalkenylene group, substituted        C₁-C₁₀ heterocycloalkenylene group, the substituted C₆-C₆₀        arylene group, substituted C₁-C₆₀ heteroarylene group, the        substituted divalent non-aromatic condensed polycyclic group,        the divalent non-aromatic condensed heteropolycyclic group, the        substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl        group, substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀        alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the        substituted C₁-C₁₀ heterocycloalkyl group, the substituted        C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀        heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the        substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀        arylthio group, the substituted C₁-C₆₀ heteroaryl group, or the        substituted monovalent non-aromatic condensed polycyclic group        and substituted monovalent non-aromatic condensed        heteropolycyclic group is selected from:    -   deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀        alkynyl group, and a C₁-C₆₀ alkoxy group;    -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl        group, and a C₁-C₆₀ alkoxy group, each substituted with at least        one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,        a cyano group, a nitro group, an amidino group, a hydrazino        group, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀        heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀        heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy        group, C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a        monovalent non-aromatic condensed polycyclic group, a monovalent        non-aromatic condensed heteropolycyclic group,        —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₆)(Q₁₇), —C(═O)(Q₁₁),        —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);    -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a        C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a        C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio        group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic        condensed polycyclic group, a monovalent non-aromatic condensed        heteropolycyclic group, a biphenyl group, and a terphenyl group;    -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a        C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a        C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio        group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic        condensed polycyclic group, a monovalent non-aromatic condensed        heteropolycyclic group, a biphenyl group, and a terphenyl group,        each substituted with at least one selected from deuterium, —F,        —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an        amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀        alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a        C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀        heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀        heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy        group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a        monovalent non-aromatic condensed polycyclic group, a monovalent        non-aromatic condensed heteropolycyclic group, a biphenyl group,        a terphenyl group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂),        —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂);        and    -   —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),    -   wherein Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, Q₃₁ to Q₃₃, and Q₄₁ to        Q₄₃ are each independently selected from hydrogen, deuterium,        —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro        group, an amidino group, a hydrazino group, a hydrazono group, a        C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl        group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a        C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a        C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀        heteroaryl group, a monovalent non-aromatic condensed polycyclic        group, a monovalent non-aromatic condensed heteropolycyclic        group, a biphenyl group, and a terphenyl group.

According to one or more exemplary embodiment of the present invention,an organic light-emitting device includes a first electrode; a secondelectrode facing the first electrode; and an organic layer disposedbetween the first electrode and the second electrode. The organic layerincludes a first compound represented by Formula 1. The organic layerincludes a second compound represented by one of Formulae 2A to 2C.

BRIEF DESCRIPTION OF THE DRAWING

The above and other features of the present invention will become moreapparent by describing in detail exemplary embodiments thereof, withreference to the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional diagram illustrating an organiclight-emitting device according to an exemplary embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments of the present invention will be described belowin more detail with reference to the accompanying drawings. “and/or”includes any exemplary embodiments may have different forms and shouldnot be construed as being limited to the exemplary embodiments of thepresent invention described herein.

Like reference numerals may refer to like elements throughout thespecification and drawings.

Sizes of elements in the drawings may be exaggerated for clarity ofdescription.

It will be understood that when a component, such as a layer, a film, aregion, or a plate, is referred to as being “on” another component, thecomponent can be directly on the other component or interveningcomponents may be present.

An organic light-emitting device according to an exemplary embodiment ofthe present invention may include a first electrode, a second electrode,and an organic layer. The organic layer may be disposed between thefirst electrode and the second electrode. The organic layer may includean emission layer.

The first electrode may be an anode. The second electrode may be acathode. The first electrode and the second electrode may be the same asdescribed herein.

The organic layer may include a first compound represented by Formula 1.The organic layer may include a second compound represented by one ofFormulae 2A to 2C.

In Formulae 1 and 2A to 2C:

-   -   X₁ may be selected from C(R₄)(R₅) and Si(R₄)(R₅), in which R₄        and R₅ may optionally be linked to form a ring;    -   X₂ may be selected from O, S, C(Z₂₁)(Z₂₂), N(Z₂₃), and        Si(Z₂₄)(Z₂₅); and    -   Z₂₁ to Z₂₅ may each independently be selected from hydrogen,        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group, a        fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl        group, a dibenzofluorenyl group, a phenanthrenyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a        triazinyl group, —Si(Q₄₁)(Q₄₂)(Q₄₃), —N(Q₄₁)(Q₄₂), —B(Q₄₁)(Q₄₂),        —C(═O)(Q₄₁), —S(═O)₂(Q₄₁), and —P(═O)(Q₄₁)(Q₄₂).

In Formulae 1 and 2A to 2C, L₁, L₁₁, L₁₂, L₂₁ to L₂₃, and L₃₁ to L₃₅ mayeach independently be selected from a substituted or unsubstitutedC₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group.

According to an exemplary embodiment of the present invention, L₁, L₁₁,L₁₂, L₂₁ to L₂₃, and L₃₁ to L₃₅ in Formulae 1 and 2A to 2C may eachindependently be selected from:

-   -   a phenylene group, a pentalenylene group, an indenylene group, a        naphthylene group, an azulenylene group, a heptalenylene group,        an indacenylene group, an acenaphthylene group, a fluorenylene        group, a spiro-bifluorenylene group, a benzofluorenylene group,        a dibenzofluorenylene group, a phenalenylene group, a        phenanthrenylene group, an anthracenylene group, a        fluoranthenylene group, a triphenylenylene group, a pyrenylene        group, a chrysenylene group, a naphthacenylene group, a        picenylene group, a perylenylene group, a pentaphenylene group,        a hexacenylene group, a pentacenylene group, a rubicenylene        group, a coronenylene group, an ovalenylene group, a pyrrolylene        group, a thiophenylene group, a furanylene group, an        imidazolylene group, a pyrazolylene group, a thiazolylene group,        an isothiazolylene group, an oxazolylene group, an isoxazolylene        group, a pyridinylene group, a pyrazinylene group, a        pyrimidinylene group, a pyridazinylene group, an isoindolylene        group, an indolylene group, an indazolylene group, a purinylene        group, a quinolinylene group, an isoquinolinylene group, a        benzoquinolinylene group, a phthalazinylene group, a        naphthyridinylene group, a quinoxalinylene group, a        quinazolinylene group, a cinnolinylene group, a carbazolylene        group, a phenanthridinylene group, an acridinylene group, a        phenanthrolinylene group, a phenazinylene group, a        benzimidazolylene group, a benzofuranylene group, a        benzothiophenylene group, an isobenzothiazolylene group, a        benzoxazolylene group, an isobenzoxazolylene group, a        triazolylene group, a tetrazolylene group, an oxadiazolylene        group, a triazinylene group, a dibenzofuranylene group, a        dibenzothiophenylene group, a dibenzosilolylene group, a        benzocarbazolylene group, a dibenzocarbazolylene group, a        thiadiazolylene group, an imidazopyridinylene group, and an        imidazopyrimidinylene group; and    -   a phenylene group, a pentalenylene group, an indenylene group, a        naphthylene group, an azulenylene group, a heptalenylene group,        an indacenylene group, an acenaphthylene group, a fluorenylene        group, a spiro-bifluorenylene group, a benzofluorenylene group,        a dibenzofluorenylene group, a phenalenylene group, a        phenanthrenylene group, an anthracenylene group, a        fluoranthenylene group, a triphenylenylene group, a pyrenylene        group, a chrysenylene group, a naphthacenylene group, a        picenylene group, a perylenylene group, a pentaphenylene group,        a hexacenylene group, a pentacenylene group, a rubicenylene        group, a coronenylene group, an ovalenylene group, a pyrrolylene        group, a thiophenylene group, a furanylene group, an        imidazolylene group, a pyrazolylene group, a thiazolylene group,        an isothiazolylene group, an oxazolylene group, an isoxazolylene        group, a pyridinylene group, a pyrazinylene group, a        pyrimidinylene group, a pyridazinylene group, an isoindolylene        group, an indolylene group, an indazolylene group, a purinylene        group, a quinolinylene group, an isoquinolinylene group, a        benzoquinolinylene group, a phthalazinylene group, a        naphthyridinylene group, a quinoxalinylene group, a        quinazolinylene group, a cinnolinylene group, a carbazolylene        group, a phenanthridinylene group, an acridinylene group, a        phenanthrolinylene group, a phenazinylene group, a        benzimidazolylene group, a benzofuranylene group, a        benzothiophenylene group, an isobenzothiazolylene group, a        benzoxazolylene group, an isobenzoxazolylene group, a        triazolylene group, a tetrazolylene group, an oxadiazolylene        group, a triazinylene group, a dibenzofuranylene group, a        dibenzothiophenylene group, a dibenzosilolylene group, a        benzocarbazolylene group, a dibenzocarbazolylene group, a        thiadiazolylene group, an imidazopyridinylene group, and an        imidazopyrimidinylene group, each substituted with at least one        selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a        cyano group, a nitro group, an amidino group, a hydrazino group,        a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,        a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cyclopentenyl group, a cyclohexenyl group, a phenyl group, a        biphenyl group, a terphenyl group, a pentalenyl group, an        indenyl group, a naphthyl group, an azulenyl group, a heptalenyl        group, an indacenyl group, an acenaphthyl group, a fluorenyl        group, a spiro-bifluorenyl group, a benzofluorenyl group, a        dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        naphthacenyl group, a picenyl group, a perylenyl group, a        pentaphenyl group, a hexacenyl group, a pentacenyl group, a        rubicenyl group, a coronenyl group, an ovalenyl group, a        pyrrolyl group, a thiophenyl group, a furanyl group, an        imidazolyl group, a pyrazolyl group, a thiazolyl group, an        isothiazolyl group, an oxazolyl group, an isoxazolyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, an isoindolyl group, an indolyl group, an        indazolyl group, a purinyl group, a quinolinyl group, an        isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl        group, a naphthyridinyl group, a quinoxalinyl group, a        quinazolinyl group, a cinnolinyl group, a carbazolyl group, a        phenanthridinyl group, an acridinyl group, a phenanthrolinyl        group, a phenazinyl group, a benzimidazolyl group, a        benzofuranyl group, a benzothiophenyl group, an        isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a        dibenzothiophenyl group, a dibenzosilolylene group, a        benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl        group, an imidazopyridinyl group, an imidazopyrimidinyl group,        Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

According to one or more exemplary embodiments of the present invention,L₁, L₁₁, L₁₂, L₂₁ to L₂₃, and L₃₁ to L₃₅ in Formulae 1 and 2A to 2C mayeach independently be selected from groups represented by Formulae 3-1to 3-42; however, exemplary embodiments of the present invention are notlimited thereto:

In Formulae 3-1 to 3-42:

-   -   Y₁ may be selected from O, S, C(Z₃)(Z₄), N(Z₅), and Si(Z₆)(Z₇);    -   Z₁ to Z₇ may each independently be selected from hydrogen,        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group, a        fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl        group, a dibenzofluorenyl group, a phenanthrenyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a        triazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),        —C(O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂);    -   Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀        alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl        group, a terphenyl group, and a naphthyl group;    -   d2 may be an integer selected from 1 and 2;    -   d3 may be an integer selected from 1 to 3;    -   d4 may be an integer selected from 1 to 4;    -   d5 may be an integer selected from 1 to 5;    -   d6 may be an integer selected from 1 to 6;    -   d8 may be an integer selected from 1 to 8; and    -   * and *′ may each indicate a binding site to an adjacent atom.

In some exemplary embodiments of the present invention, L₁, L₁₁, L₁₂,L₂₁ to L₂₃, and L₃₁ to L₃₅ in Formulae 1 and 2A to 2C may eachindependently be selected from groups represented by Formulae 4-1 to4-31; however, exemplary embodiments of the present invention are notlimited thereto:

In Formulae 4-1 to 4-32, *and *′ may each indicate a binding site to anadjacent atom.

In Formula 1, L₁ may be selected from:

-   -   a phenylene group, a naphthylene group, a fluorenylene group, a        benzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, and a chrysenylene        group; and    -   a phenylene group, a naphthylene group, a fluorenylene group, a        benzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, and a chrysenylene        group, each substituted with at least one selected from        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group,        —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, or a naphthyl group; however, exemplary embodiments of thepresent invention are not limited thereto.

In Formula 2A:

-   -   L₁₁ and L₁₂ may each independently be selected from:    -   a phenylene group, a naphthylene group, a fluorenylene group, a        benzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, and a chrysenylene        group; and    -   a phenylene group, a naphthylene group, a fluorenylene group, a        benzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, and a chrysenylene        group, each substituted with at least one selected from        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group,        —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

L₂₁ to L₂₃ and L₃₁ to L₃₅ in Formulae 2B and 2C may each independentlybe selected from:

-   -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, a chrysenylene group,        a pyridinylene group, a pyrazinylene group, a pyrimidinylene        group, a pyridazinylene group, a quinolinylene group, an        isoquinolinylene group, a quinoxalinylene group, a        quinazolinylene group, a carbazolylene group, and a triazinylene        group; and    -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, a chrysenylene group,        a pyridinylene group, a pyrazinylene group, a pyrimidinylene        group, a pyridazinylene group, a quinolinylene group, an        isoquinolinylene group, a quinoxalinylene group, a        quinazolinylene group, a carbazolylene group, and a triazinylene        group, each substituted with at least one selected from        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group, a        fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl        group, a dibenzofluorenyl group, a phenanthrenyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, an isoindolyl group, a quinolinyl group, an        isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group,        a carbazolyl group, a triazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),        —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and        —P(═O)(Q₃₁)(Q₃₂); however, exemplary embodiments of the present        invention are not limited thereto.

In Formula 1, a1 may indicate the number of L₁(s). a1 may be an integerselected from 0 to 5. For example, a1 may be an integer selected from 1to 3; however, exemplary embodiments of the present invention are notlimited thereto. When a1 is 0, *-(L₁)_(a1)-*′ may be a single bond. Whena1 is 2 or greater, at least two L₁(s) may be the same as or differentfrom each other.

In Formula 2A, a11 may indicate the number of L₁₁(s). a11 may be aninteger selected from 0 to 5. For example, a11 may be an integerselected from 0 or 1; however, exemplary embodiments of the presentinvention are not limited thereto. When a11 is 0, *-(L₁₁)_(a11)-*′ maybe a single bond. When a11 is 2 or greater, at least two L₁₁(s) may bethe same as or different from each other.

In Formula 2A, a12 may indicate the number of L₁₂(s). a12 may be aninteger selected from 0 to 5. For example, a12 may be 0; however,exemplary embodiments of the present invention are not limited thereto.When a12 is 0, *-(L₁₂)_(a12)-*′ may be a single bond. When a12 is 2 orgreater, at least two L₁₂(s) may be the same or different from eachother.

In Formulae 2B and 2C, a21 may indicate the number of L₂₁(s); a22 mayindicate the number of L₂₂(s); a23 may indicate the number of L₂₃(s);a31 may indicate the number of L₃₁(s); a32 may indicate the number ofL₃₂(s); a33 may indicate the number of L₃₃(s); a34 may indicate thenumber of L₃₄(s); and a35 may indicates the number of L₃₅(s), which mayeach independently be selected from 0 to 5. According to some exemplaryembodiments of the present invention, a21 to a23 and a31 to a34 may eachindependently be an integer selected from 0 to 4, and a35 may be aninteger selected from 2 to 4; however, exemplary embodiments of thepresent invention are not limited thereto.

When a21 is 0, *-(L₂₁)_(a21)-*′ may be a single bond. When a22 is 0,*-(L₂₂)_(a22)-*′ may be a single bond. When a23 is 0, *-(L₂₃)_(a23)-*′may be a single bond. When a31 is 0, *-(L₃₁)_(a31)-*′ may be a singlebond. When a32 is 0, *-(L₂₃)_(a23)-*′ may be a single bond. When a33 is0, *-(L₃₃)_(a33)-*′ may be a single bond. When a34 is 0,*-(L₃₄)_(a34)-*′ may be a single bond. When a35 is 0, *-(L₃₅)_(a35)-*′may be a single bond. When a21 is 2 or greater, at least two of L₂₁(s)may be the same as or different from each other; when a22 is 2 orgreater, at least two L₂₂(s) may be the same as or different from eachother; when a23 is 2 or greater, at least two L₂₃(s) may be the same asor different from each other; when a31 is 2 or greater, at least two L₃₁(s) may be the same as or different from each other; when a32 is 2 orgreater, at least two L₃₂(s) may be the same as or different from eachother; when a33 is 2 or greater, at least two L₃₃(s) may be the same asor different from each other; when a34 is 2 or greater, at least twoL₃₄(s) may be the same as or different from each other; and when a35 is2 or greater, at least two L₃₅(s) may be the same as or different fromeach other.

According to an exemplary embodiment of the present invention, A₁ may beselected from P(═O)(R₄₁)(R₄₂) or S(═O)₂(R₄₃).

According to an exemplary embodiment of the present invention, b1 mayindicate the number of A₁(s). b1 may be an integer selected from 1 to 5.According to an exemplary embodiment of the present invention, b1 may be1; however, exemplary embodiments of the present invention are notlimited thereto. When b1 is 2 or greater, at least two A₁(s) may be thesame as or different from each other.

Ar₁₁ in Formula 1 may be selected from a substituted or unsubstitutedC₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, asubstituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group.

According to an exemplary embodiment of the present invention, Ar₁₁ inFormula 2A may be selected from:

-   -   a phenyl group, a biphenyl group, a terphenyl group, a        pentalenyl group, an indenyl group, a naphthyl group, an        azulenyl group, a heptalenyl group, an indacenyl group, an        acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,        a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl        group, a phenanthrenyl group, an anthracenyl group, a        fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a        chrysenyl group, a naphthacenyl group, a picenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a rubicenyl group, a coronenyl group, an        ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl        group, a pyridazinyl group, an isoindolyl group, an indolyl        group, an indazolyl group, a purinyl group, a quinolinyl group,        an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl        group, a naphthyridinyl group, a quinoxalinyl group, a        quinazolinyl group, a cinnolinyl group, a carbazolyl group, a        phenanthridinyl group, an acridinyl group, a phenanthrolinyl        group, a phenazinyl group, a benzimidazolyl group, a        benzofuranyl group, a dibenzofuranyl group, a benzothiophenyl        group, a dibenzothiophenyl group, an isobenzothiazolyl group, a        benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group,        a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a        benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl        group, an imidazopyridinyl group, an imidazopyrimidinyl group, a        naphthoxanthenyl group, a dibenzosilolyl group, a        benzonaphthofuranyl group, and a benzopyrenyl group; and    -   a phenyl group, a biphenyl group, a terphenyl group, a        pentalenyl group, an indenyl group, a naphthyl group, an        azulenyl group, a heptalenyl group, an indacenyl group, an        acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,        a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl        group, a phenanthrenyl group, an anthracenyl group, a        fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a        chrysenyl group, a naphthacenyl group, a picenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a rubicenyl group, a coronenyl group, an        ovalenyl group, a pyrrolyl group, a thiophenyl group, a furanyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl        group, a pyridazinyl group, an isoindolyl group, an indolyl        group, an indazolyl group, a purinyl group, a quinolinyl group,        an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl        group, a naphthyridinyl group, a quinoxalinyl group, a        quinazolinyl group, a cinnolinyl group, a carbazolyl group, a        phenanthridinyl group, an acridinyl group, a phenanthrolinyl        group, a phenazinyl group, a benzimidazolyl group, a        benzofuranyl group, a dibenzofuranyl group, a benzothiophenyl        group, a dibenzothiophenyl group, an isobenzothiazolyl group, a        benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group,        a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a        benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl        group, an imidazopyridinyl group, an imidazopyrimidinyl group, a        naphthoxanthenyl group, a dibenzosilolyl group, a        benzonaphthofuranyl group, and a benzopyrenyl group, each        substituted with at least one selected from deuterium, —F, —Cl,        —Br, —I, a hydroxyl group, a cyano group, a nitro group, an        amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀        alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a        cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a        cyclohexenyl group, a phenyl group, a biphenyl group, a        terphenyl group, a pentalenyl group, an indenyl group, a        naphthyl group, an azulenyl group, a heptalenyl group, an        indacenyl group, an acenaphthyl group, a fluorenyl group, a        spiro-bifluorenyl group, a benzofluorenyl group, a        dibenzofluorenyl group, a phenalenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        naphthacenyl group, a picenyl group, a perylenyl group, a        pentaphenyl group, a hexacenyl group, a pentacenyl group, a        rubicenyl group, a coronenyl group, an ovalenyl group, a        pyrrolyl group, a thiophenyl group, a furanyl group, an        imidazolyl group, a pyrazolyl group, a thiazolyl group, an        isothiazolyl group, an oxazolyl group, an isoxazolyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, an isoindolyl group, an indolyl group, an        indazolyl group, a purinyl group, a quinolinyl group, an        isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl        group, a naphthyridinyl group, a quinoxalinyl group, a        quinazolinyl group, a cinnolinyl group, a carbazolyl group, a        phenanthridinyl group, an acridinyl group, a phenanthrolinyl        group, a phenazinyl group, a benzimidazolyl group, a        benzofuranyl group, a benzothiophenyl group, an        isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a        dibenzothiophenyl group, a dibenzosilolyl group, a        benzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl        group, an imidazopyridinyl group, an imidazopyrimidinyl group,        —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

According to an exemplary embodiment of the present invention, Ar₁₁ inFormula 2A may be selected from groups represented by Formulae 5-1 to5-19; however, exemplary embodiments of the present invention are notlimited thereto.

In Formulae 5-1 to 5-19:

-   -   Y₃₁ may be selected from O, S, C(Z₃₃)(Z₃₄), N(Z₃₅), and        Si(Z₃₆)(Z₃₇);    -   Z₃₁ to Z₃₉ may each independently be selected from:    -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a        phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a pyrenyl group, a chrysenyl group,        a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a triazinyl group,        —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂);    -   Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀        alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl        group, a terphenyl group, and a naphthyl group;    -   e3 may be an integer selected from 1 to 3;    -   e4 may be an integer selected from 1 to 4;    -   e5 may be an integer selected from 1 to 5;    -   e6 may be an integer selected from 1 to 6;    -   e7 may be an integer selected from 1 to 7;    -   e8 may be an integer selected from 1 to 8;    -   e9 may be an integer selected from 1 to 9; and    -   * may indicate a binding site to an adjacent atom.

According to an exemplary embodiment of the present invention, Ar₁₁ inFormula 2A may be selected from groups represented by Formulae 6-1 to6-43; however, exemplary embodiments of the present invention are notlimited thereto:

In Formulae 6-1 to 6-43, * may indicate a binding site to an adjacentatom.

According to an exemplary embodiment of the present invention, Ar₁₁ inFormula 2A may be selected from:

-   -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, an anthracenyl group, a pyrenyl group,        a chrysenyl group, a pyridinyl group, a dibenzofuranyl group,        and a dibenzothiophenyl group; and    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, an anthracenyl group, a pyrenyl group,        a chrysenyl group, a pyridinyl group, a dibenzofuranyl group,        and a dibenzothiophenyl group, each substituted with at least        one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,        a cyano group, a nitro group, an amidino group, a hydrazino        group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy        group, a phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),        —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group; however, exemplary embodiments of thepresent invention are not limited thereto.

According to an exemplary embodiment of the present invention, b11 mayindicate the number of Ar₁₁(s). b11 may be an integer selected from 1 to5. According to an exemplary embodiment of the present invention, b11may be 1; however, exemplary embodiments of the present invention arenot limited thereto. When b11 is 2 or greater, at least two Ar₁₁(s) maybe the same as or different from each other.

According to an exemplary embodiment of the present invention, inFormulae 1 and 2A to 2C, R₁ to R₅, R₁₁ to R₁₄, R₂₁ to R₂₃, R₃₁ to R₃₄,and R₄₁ to R₄₃ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substitutedor unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂),—C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂).

According to an exemplary embodiment of the present invention, R₁ to R₅,R₁₁ to R₁₄, R₂₁ to R₂₃, R₃₁ to R₃₄, and R₄₁ to R₄₃ in Formulae 1 and 2Ato 2C may each independently be selected from:

-   -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy        group;    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a triphenylenyl group, a pyrenyl        group, a chrysenyl group, a pyrrolyl group, a thiophenyl group,        a furanyl group, an imidazolyl group, a pyrazolyl group, a        thiazolyl group, an isothiazolyl group, an oxazolyl group, an        isoxazolyl group, a pyridinyl group, a pyrazinyl group, a        pyrimidinyl group, a pyridazinyl group, a quinolinyl group, an        isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl        group, a quinazolinyl group, a benzimidazolyl group, a        benzofuranyl group, a benzothiophenyl group, an        isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group,        a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl        group, a dibenzosilolyl group, an imidazopyridinyl group, and an        imidazopyrimidinyl group;    -   a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a        biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl        group, a spiro-bifluorenyl group, a benzofluorenyl group, a        dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl        group, a triphenylenyl group, a pyrenyl group, a chrysenyl        group, a pyrrolyl group, a thiophenyl group, a furanyl group, an        imidazolyl group, a pyrazolyl group, a thiazolyl group, an        isothiazolyl group, an oxazolyl group, an isoxazolyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl        group, a benzimidazolyl group, a benzofuranyl group, a        benzothiophenyl group, an isobenzothiazolyl group, a        benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl        group, a triazinyl group, a carbazolyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a dibenzosilolyl group, an        imidazopyridinyl group, and an imidazopyrimidinyl group, each        substituted with at least one selected from deuterium, —F, —Cl,        —Br, —I, a hydroxyl group, a cyano group, a nitro group, an        amidino group, a hydrazino group, a hydrazono group, a C₁-C₁₀        alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl        group, a terphenyl group, a naphthyl group, a fluorenyl group, a        spiro-bifluorenyl group, a benzofluorenyl group, a        dibenzofluorenyl group, a phenanthrenyl group, an anthracenyl        group, a triphenylenyl group, a pyrenyl group, a chrysenyl        group, a pyrrolyl group, a thiophenyl group, a furanyl group, an        imidazolyl group, a pyrazolyl group, a thiazolyl group, an        isothiazolyl group, an oxazolyl group, an isoxazolyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl        group, a benzimidazolyl group, a benzofuranyl group, a        benzothiophenyl group, an isobenzothiazolyl group, a        benzoxazolyl group, an isobenzoxazolyl group, an oxadiazolyl        group, a triazinyl group, a carbazolyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a dibenzosilolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group,        —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂); or —Si(Q₁)(Q₂)(Q₃),        —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂).

Q₁ to Q₃ and Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

According to an exemplary embodiment of the present invention, inFormula 1:

-   -   X₁ may be selected from C(R₄)(R₅) and Si(R₄)(R₅), in which R₄        and R₅ may be bound to form a ring;    -   A₁ may be selected from P(═O)(R₄₁)(R₄₂) and S(═O)₂(R₄₃); and    -   R₁ to R₅ and R₄₁ to R₄₃ may each independently be selected from:    -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy        group, a phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, an anthracenyl group, a pyrenyl group, a        chrysenyl group, and a pyridinyl group;    -   a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a        biphenyl group, a terphenyl group, a naphthyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, and a        pyridinyl group, each substituted with at least one selected        from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a        phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a pyridinyl group, a pyrimidinyl group, a triazinyl        group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),        —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂); and    -   —Si(Q₁)(Q₂)(Q₃), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂).

Q₁ to Q₃ and Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, or a naphthyl group; however, exemplary embodiments ofthe present invention are not limited thereto.

According to an exemplary embodiment of the present invention, inFormulae 2A to 2C:

-   -   R₁₁ to R₁₄ may each independently be selected from:    -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy        group, a phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, an anthracenyl group, a pyrenyl group, a        chrysenyl group, and a pyridinyl group;    -   a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a        biphenyl group, a terphenyl group, a naphthyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, and a        pyridinyl group, each substituted with at least one selected        from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a        phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a pyridinyl group, a pyrimidinyl group, a triazinyl        group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),        —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and    -   —Si(Q₁)(Q₂)(Q₃), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂);    -   Q₁ to Q₃ and Q₃₁ to Q₃₃ may each independently be selected from        a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a        biphenyl group, a terphenyl group, and a naphthyl group; and    -   R₂₁ to R₂₃ and R₃₁ to R₃₄ may each independently be selected        from:    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a pyrenyl group, a chrysenyl group,        a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, and a triazinyl group; and    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a pyrenyl group, a chrysenyl group,        a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, and a triazinyl group, each substituted        with at least one selected from deuterium, —F, —Cl, —Br, —I, a        hydroxyl group, a cyano group, a nitro group, an amidino group,        a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a        C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a        terphenyl group, a naphthyl group, an azulenyl group, a        fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl        group, a dibenzofluorenyl group, a phenanthrenyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a        triazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),        —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂); however,        exemplary embodiments of the present invention are not limited        thereto.

According to an exemplary embodiment of the present invention, c1 mayindicate the number of R₁(s). c1 may be an integer selected from 0 to 4.When c1 is 2 or greater, at least two R₁(s) may be the same as ordifferent from each other. c11 may indicate the number of R₁₁(s). c11may be an integer selected from 0 to 4. When c11 is 2 or greater, atleast two R₁₁(s) may be the same as or different from each other. c12may indicate the number of R₁₂(s). c12 may be an integer selected from 0to 4. When c12 is 2 or greater, at least two R₁₂(s) may be the same asor different from each other. c13 may indicate the number of R₁₃(s). c13may be an integer selected from 0 to 4. When c13 is 2 or greater, atleast two R₁₃(s) may be the same as or different from each other. c14may indicate the number of R₁₄(s). c14 may be an integer selected from 0to 4. When c4 is 2 or greater, at least two R₁₄(s) may be the same as ordifferent from each other.

c2 may indicate the number of R₂(s). c2 may be an integer selected from0 to 3. When c2 is 2 or greater, at least two R₂(s) may be the same asor different from each other.

c3 indicates the number of R₃(s). c3 may be an integer selected from 0to 2. When c3 is 2 or greater, at least two R₃(s) may be the same as ordifferent from each other.

c21 may indicate the number of R₂₁(s). c22 may indicate the number of(s). c23 may indicate the number of R₂₃(s). c31 may indicate the numberof R₃₁(s). c32 may indicate the number of R₃₂(s). c33 may indicate thenumber of R₃₃(s). c34 may indicate the number of R₃₄(s). c21 to c23 andc31 to c34 may each independently be an integer selected from 1 to 5.When c21 is 2 or greater, at least two R₂₁(s) may be the same as ordifferent from each other. When c22 is 2 or greater, at least two R₂₂(s)may be the same as or different from each other. When c23 is 2 orgreater, at least two R₂₃(s) may be the same as or different from eachother. When c31 is 2 or greater, at least two R₃₁(s) may be the same asor different from each other. When c32 is 2 or greater, at least twoR₃₂(s) may be the same as or different from each other. When c33 is 2 orgreater, at least two R₃₃(s) may be the same as or different from eachother. When c34 is 2 or greater, at least two R₃₄(s) may be the same asor different from each other.

According to one or more exemplary embodiments of the present invention,the first compound may be represented by one of Formulae 1-1 to 1-4. Thesecond compound may be selected from compounds represented by Formulae2a-1 to 2a-4, 2b-1 to 2b-4, and 2c-1; compounds represented by Formula2B in which L₂₁ may be selected from a fluorenylene group, aspiro-bifluorenylene group, a carbazolylene group, a dibenzofuranylenegroup, and a dibenzothiophenylene group; compounds represented byFormula 2B in which R₂₁ may be selected from a fluorenyl group, aspiro-bifluorenyl group, a carbazolyl group, a dibenzofuranyl group, anda dibenzothiophenyl group; or compounds represented by Formula 2B inwhich L₂₁ to L₂₃ may be a phenylene group and R₂₁ to R₂₃ may be a phenylgroup.

In Formulae 1-1 to 1-4, 2a-1 to 2a-4, 2b-1 to 2b-4, and 2c-1, L₁, L₁₁,L₂₁ to L₂₃, L₃₁ to L₃₄, a1, a11, a21 to a23, a31 to a35, Ar₁₁, loll, R₁to R₅, R₁₁ to R₁₄, R₂₃, R₃₁ to R₃₄, R₄₁ to R₄₃, c1 to c3, c11 to c14,c23, c31 to c34, and X₂ may be the same as described herein;

-   -   X₃ and X₄ may be the same as X₂ as described herein;    -   R₂₁₁ to R₂₁₈ and R₂₂₃ are the same as R₁₁ to R₁₄ as described        herein;    -   c211, c214 to c218, and c223 may each independently be an        integer selected from 0 to 4. when c211 is 2 or greater, at        least two R₂₁₁(s) may be the same as or different from each        other; when c214 is 2 or greater, at least two R₂₁₄(s) may be        the same as or different from each other; when c215 is 2 or        greater, at least two R₂₁₅(s) may be the same as or different        from each other; when c216 is 2 or greater, at least two R₂₁₆(s)        may be the same as or different from each other; when c217 is 2        or greater, at least two R₂₁₇(s) may be the same as or different        from each other; when c218 is 2 or greater, at least two R₂₁₈(s)        may be the same as or different from each other; and when c223        is 2 or greater, at least two R₂₂₃(s) may be the same as or        different from each other; and    -   c212 and c213 may each independently be an integer selected from        0 to 3; when c212 is 2 or greater, at least two R₂₁₂(s) may be        the same as or different from each other; and when c213 is 2 or        greater, at least two R₂₁₃(s) may be the same as or different        from each other.

According to an exemplary embodiment of the present invention, inFormulae 1-1 to 1-4, 2a-1 to 2a-4, 2b-1 to 2b-6, and 2c-1:

-   -   L₁ and L₁₁ may each independently be selected from:    -   a phenylene group, a naphthylene group, a fluorenylene group, a        benzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, and a chrysenylene        group; and    -   a phenylene group, a naphthylene group, a fluorenylene group, a        benzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, and a chrysenylene        group, each substituted with at least one selected from        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group,        —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂);    -   L₂₁ to L₂₃ and L₃₁ to L₃₄ may each independently be selected        from:    -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, a chrysenylene group,        a pyridinylene group, a pyrazinylene group, a pyrimidinylene        group, a pyridazinylene group, a quinolinylene group, an        isoquinolinylene group, a quinoxalinylene group, a        quinazolinylene group, a carbazolylene group, and a triazinylene        group; and    -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, a chrysenylene group,        a pyridinylene group, a pyrazinylene group, a pyrimidinylene        group, a pyridazinylene group, a quinolinylene group, an        isoquinolinylene group, a quinoxalinylene group, a        quinazolinylene group, a carbazolylene group, and a triazinylene        group, each substituted with at least one selected from        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group, a        fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl        group, a dibenzofluorenyl group, a phenanthrenyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, an isoindolyl group, a quinolinyl group, an        isoquinolinyl group, a quinoxalinyl group, a quinazolinyl group,        a carbazolyl group, a triazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),        —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and        —P(═O)(Q₃₁)(Q₃₂),    -   a1 may be an integer selected from 1 to 3;    -   a11 may be an integer selected from 0 or 1;    -   a21 to a23 and a31 to a34 may each independently be an integer        selected from 0 to 4;    -   a35 may be an integer selected from 2 to 4;    -   R₁ to R₅, R₁₁ to R₁₄, and R₄₁ to R₄₃ may each independently be        selected from:    -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy        group, a phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, an anthracenyl group, a pyrenyl group, a        chrysenyl group, and a pyridinyl group;    -   a C₁-C₁₀ alkyl group, and a C₁-C₁₀ alkoxy group, a phenyl group,        a biphenyl group, a terphenyl group, a naphthyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, and a        pyridinyl group, each substituted with at least one selected        from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a C₁-C₁₀ alkyl group, a        C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a        terphenyl group, a naphthyl group, a pyridinyl group, a        pyrimidinyl group, a triazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),        —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and        —P(═O)(Q₃₁)(Q₃₂); and    -   —Si(Q₁)(Q₂)(Q₃), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂);    -   Q₁ to Q₃ and Q₃₁ to Q₃₃ may each independently be selected from        a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a        biphenyl group, a terphenyl group, and a naphthyl group; and    -   R₂₁ to R₂₃ and R₃₁ to R₃₄ may each independently be selected        from:    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a pyrenyl group, a chrysenyl group,        a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, and a triazinyl group; and    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a pyrenyl group, a chrysenyl group,        a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, and a triazinyl group, each substituted        with at least one selected from deuterium, —F, —Cl, —Br, —I, a        hydroxyl group, a cyano group, a nitro group, an amidino group,        a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a        C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a        terphenyl group, a naphthyl group, an azulenyl group, a        fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl        group, a dibenzofluorenyl group, a phenanthrenyl group, an        anthracenyl group, a pyrenyl group, a chrysenyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, a quinolinyl group, an isoquinolinyl group, a        quinoxalinyl group, a quinazolinyl group, a carbazolyl group, a        triazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),        —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

According to an exemplary embodiment of the present invention, inFormulae 1-1 to 1-4, 2a-1 to 2a-4, 2b-1 to 2b-6, and 2c-1:

-   -   L₁ and L₁₁ may each independently be selected from:    -   a phenylene group, a naphthylene group, a phenanthrenylene        group, an anthracenylene group, a pyrenylene group, and a        chrysenylene group; and    -   a phenylene group, a naphthylene group, a phenanthrenylene        group, an anthracenylene group, a pyrenylene group, and a        chrysenylene group, each substituted with at least one selected        from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a        phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),        —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂);    -   L₂₁ to L₂₃ and L₃₁ to L₃₄ may each independently be selected        from:    -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, a chrysenylene group,        a carbazolylene group, and a triazinylene group; and    -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a pyrenylene group, a chrysenylene group,        a carbazolylene group, and a triazinylene group, each        substituted with at least one selected from deuterium, —F, —Cl,        —Br, —I, a hydroxyl group, a cyano group, a nitro group, an        amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀        alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl        group, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),        —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and        —P(═O)(Q₃₁)(Q₃₂);    -   a1 may be an integer selected from 1 to 3;    -   a11 may be an integer selected from 0 and 1;    -   a21 to a23 and a31 to a34 may each independently be selected        from 0 to 4;    -   a35 may be an integer selected from 2 to 4;    -   R₁ to R₅, R₁₁ to R₁₄, and R₄₁ to R₄₃ may each independently be        selected from:    -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy        group, a phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, and an anthracenyl group;    -   a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a        biphenyl group, a terphenyl group, a naphthyl group, and an        anthracenyl group, each substituted with at least one selected        from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a        phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a pyridinyl group, a pyrimidinyl group, a triazinyl        group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),        —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂); and    -   —Si(Q₁)(Q₂)(Q₃), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂);    -   Q₁ to Q₃ and Q₃₁ to Q₃₃ may each independently be selected from        a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a        biphenyl group, a terphenyl group, and a naphthyl group; and    -   R₂₁ to R₂₃ and R₃₁ to R₃₄ may each independently be selected        from:    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a pyrenyl group, a chrysenyl group,        a pyridinyl group, a carbazolyl group, a dibenzofuranyl group, a        dibenzothiophenyl group, a dibenzosilolyl group, and a triazinyl        group; and    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a pyrenyl group, a chrysenyl group,        a pyridinyl group, a carbazolyl group, a dibenzofuranyl group, a        dibenzothiophenyl group, a dibenzosilolyl group, and a triazinyl        group, each substituted with at least one selected from        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group, an        azulenyl group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a pyrenyl group, a chrysenyl group,        a pyridinyl group, a carbazolyl group, a triazinyl group,        —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂); however, exemplary        embodiments of the present invention are not limited thereto.

According to an exemplary embodiment of the present invention, the firstcompound may be represented by one of Compounds 1-1 to 1-30, and thesecond compound may be represented by one of Compounds 2-1 to 2-74;however, exemplary embodiments of the present invention are not limitedthereto:

The first compound represented by Formula 1 may be anelectron-transporting host. The second compound represented by one ofFormulae 2A to 2C may be a hole-transporting host.

When the first compound and the second compound are both used to form anemission layer host, injection of electrons and holes into the emissionlayer may be facilitated. Thus, relatively low-voltage driving may beachieved due to a decreased driving voltage, and maintaining balance maybe possible due to widespread excitons within the emission layer. Thus,an organic light-emitting device with relatively high efficiency may beproduced.

The emission layer of the organic layer 150 may include the firstcompound and the second compound. According to an exemplary embodimentof the present invention, the emission layer of the organic layer 150may include the first compound, and the electron transport region mayinclude the second compound. The electron transport region may bedisposed between the emission layer and the second electrode. Accordingto an exemplary embodiment of the present invention, the emission layerof the organic layer 150 may include the first compound and the secondcompound, and the electron transport region may include the secondcompound. The electron transport region may be disposed between theemission layer and the second electrode. The second compound included inthe emission layer and the second compound included in the electrontransport region may be the same as or different from each other.

According to an exemplary embodiment of the present invention, theemission layer of the organic layer 150 may include the first compound,and the hole transport region may include the second compound. The holetransport region may be disposed between the emission layer and thefirst electrode. According to an exemplary embodiment of the presentinvention, the emission layer of the organic layer 150 may include thefirst compound and the second compound, and the hole transport regionmay include the second compound. The hole transport region may bedisposed between the emission layer and the first electrode. The secondcompound included in the emission layer and the second compound includedin the hole transport region may be the same as or different from eachother.

FIG. 1 is a schematic cross-sectional diagram illustrating an organiclight-emitting device according to an exemplary embodiment of thepresent invention. Referring to FIG. 1, the organic light-emittingdevice 10 may include a first electrode 110, an organic layer 150, and asecond electrode 190.

The structure of an organic light-emitting device 10 according to anexemplary embodiment of the present invention and a method ofmanufacturing an organic light-emitting device 10 according to anexemplary embodiment of the present invention, will be described in moredetail below with reference to FIG. 1.

Referring to FIG. 1, a substrate may be disposed below the firstelectrode 110. Alternatively, the substrate may be disposed above thesecond electrode 190. The substrate may include a glass substrate or aplastic substrate. The glass substrate and the plastic substrate mayeach have a relatively high mechanical strength, thermal stability,transparency, surface smoothness, ease of handling, andwater-resistance.

The first electrode 110 may be formed by depositing or sputtering amaterial included in the first electrode 110 on the substrate. When thefirst electrode 110 is an anode, the material included in the firstelectrode 110 may include at least one material with a relatively highwork function, which may facilitate hole injection.

The first electrode 110 may be a reflective electrode, asemi-transmissive electrode, or a transmissive electrode. When the firstelectrode 110 is a transmissive electrode, a material included in thefirst electrode 110 may include indium tin oxide (ITO), indium zincoxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), or any combinationthereof; however, exemplary embodiments of the present invention are notlimited thereto. According to one or more exemplary embodiments of thepresent invention, when the first electrode 110 is a semi-transmissiveelectrode or a reflective electrode, a material included in the firstelectrode 110 may include magnesium (Mg), silver (Ag), aluminum (Al),aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In),magnesium-silver (Mg—Ag), or any combination thereof; however, exemplaryembodiments of the present invention are not limited thereto.

The first electrode 110 may have a single-layered structure.Alternatively, the first electrode 110 may have a multi-layeredstructure including two or more layers. For example, the first electrode110 may have a three-layered structure of ITO/Ag/ITO; however, thestructure of the first electrode 110 is not limited thereto.

The organic layer 150 may be disposed on the first electrode 110. Theorganic layer 150 may include an emission layer.

The organic layer 150 may include a hole transport region and anelectron transport region. The hole transport region may be disposedbetween the first electrode 110 and the emission layer. The electrontransport region may be disposed between the emission layer and thesecond electrode 190.

The hole transport region may have a single-layered structure includinga single layer including a single material. The hole transport regionmay have a single-layered structure including a single layer including aplurality of different materials. The hole transport region may have amulti-layered structure having a plurality of layers each including aplurality of different materials.

The hole transport region may include at least one layer selected from ahole injection layer (HIL), a hole transport layer (HTL), an emissionauxiliary layer, and an electron blocking layer (EBL).

For example, the hole transport region may have a single-layeredstructure. The single-layered structure may include a single layerincluding a plurality of different materials. Alternatively, the holetransport region may have a multi-layered structure. The multi-layeredstructure may include a hole injection layer/hole transport layerstructure, a hole injection layer/hole transport layer/emissionauxiliary layer structure, a hole injection layer/emission auxiliarylayer structure, a hole transport layer/emission auxiliary layerstructure, or a hole injection layer/hole transport layer/electronblocking layer structure. For each structure, the layers may besequentially stacked on the first electrode 110; however, the structureof the hole transport region is not limited thereto.

The hole transport region may include at least one selected fromm-MTDATA, TDATA, 2-TNATA, NPB (NPD), β-NPB, TPD, Spiro-TPD, Spiro-NPB,methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine(TCTA), polyaniline/dodecylbenzenesulfonic acid (Pani/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/camphor sulfonic acid (Pani/CSA),polyaniline/poly(4-styrenesulfonate) (Pani/PSS), a compound representedby Formula 201, and a compound represented by Formula 202:

In Formulae 201 and 202:

-   -   L₂₀₁ to L₂₀₄ may each independently be selected from a        substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a        substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group,        a substituted or unsubstituted C₆-C₆₀ arylene group, a        substituted or unsubstituted C₁-C₆₀ heteroarylene group, a        substituted or unsubstituted divalent non-aromatic condensed        polycyclic group, or a substituted or unsubstituted divalent        non-aromatic condensed heteropolycyclic group;    -   L₂₀₅ may be selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a        substituted or unsubstituted C₁-C₂₀ alkylene group, a        substituted or unsubstituted C₂-C₂₀ alkenylene group, a        substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a        substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group,        a substituted or unsubstituted C₆-C₆₀ arylene group, a        substituted or unsubstituted C₁-C₆₃ heteroarylene group, a        substituted or unsubstituted divalent non-aromatic condensed        polycyclic group, and a substituted or unsubstituted divalent        non-aromatic condensed heteropolycyclic group;    -   xa1 to xa4 may each independently be an integer selected from 0        to 3;    -   xa5 may be an integer selected from 1 to 10; and    -   R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be selected from a        substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a        substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a        substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or        unsubstituted C₆-C₆₀ aryloxy group, a substituted or        unsubstituted C₆-C₆₀ arylthio group, a substituted or        unsubstituted C₁-C₆₀ heteroaryl group, a substituted or        unsubstituted monovalent non-aromatic condensed polycyclic        group, and a substituted or unsubstituted monovalent        non-aromatic condensed heteropolycyclic group.

According to an exemplary embodiment of the present invention, inFormula 202, R₂₀₁ and R₂₀₂ may be chemically bonded to each other via asingle bond, a dimethyl-methylene group, or a diphenyl-methylene group,and R₂₀₃ and R₂₀₄ may optionally be chemically bonded to each other viaa single bond, a dimethyl-methylene group, or a diphenyl-methylenegroup.

According to an exemplary embodiment of the present invention, inFormulae 201 and 202:

-   -   L₂₀₁ to L₂₀₅ may each independently be selected from:    -   a phenylene group, a pentalenylene group, an indenylene group, a        naphthylene group, an azulenylene group, a heptalenylene group,        an indacenylene group, an acenaphthylene group, a fluorenylene        group, a spiro-bifluorenylene group, a benzofluorenylene group,        a dibenzofluorenylene group, a phenalenylene group, a        phenanthrenylene group, an anthracenylene group, a        fluoranthenylene group, a triphenylenylene group, a pyrenylene        group, a chrysenylene group, a naphthacenylene group, a        picenylene group, a perylenylene group, a pentaphenylene group,        a hexacenylene group, a pentacenylene group, a rubicenylene        group, a coronenylene group, an ovalenylene group, a        thiophenylene group, a furanylene group, a carbazolylene group,        an indolylene group, an isoindolylene group, a benzofuranylene        group, a benzothiophenylene group, a dibenzofuranylene group, a        dibenzothiophenylene group, a benzocarbazolylene group, a        dibenzocarbazolylene group, a dibenzosilolylene group, and a        pyridinylene group; and    -   a phenylene group, a pentalenylene group, an indenylene group, a        naphthylene group, an azulenylene group, a heptalenylene group,        an indacenylene group, an acenaphthylene group, a fluorenylene        group, a spiro-bifluorenylene group, a benzofluorenylene group,        a dibenzofluorenylene group, a phenalenylene group, a        phenanthrenylene group, an anthracenylene group, a        fluoranthenylene group, a triphenylenylene group, a pyrenylene        group, a chrysenylene group, a naphthacenylene group, a        picenylene group, a perylenylene group, a pentaphenylene group,        a hexacenylene group, a pentacenylene group, a rubicenylene        group, a coronenylene group, an ovalenylene group, a        thiophenylene group, a furanylene group, a carbazolylene group,        an indolylene group, an isoindolylene group, a benzofuranylene        group, a benzothiophenylene group, a dibenzofuranylene group, a        dibenzothiophenylene group, a benzocarbazolylene group, a        dibenzocarbazolylene group, a dibenzosilolylene group, and a        pyridinylene group, each substituted with at least one selected        from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a        cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cyclopentenyl group, a cyclohexenyl group, a phenyl group, a        biphenyl group, a terphenyl group, a phenyl group substituted        with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a        pentalenyl group, an indenyl group, a naphthyl group, an        azulenyl group, a heptalenyl group, an indacenyl group, an        acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,        a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl        group, a phenanthrenyl group, an anthracenyl group, a        fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a        chrysenyl group, a naphthacenyl group, a picenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a rubicenyl group, a coronenyl group, an        ovalenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

According to an exemplary embodiment of the present invention, xa1 toxa4 in Formulae 201 and 202 may each independently be an integerselected from 0 to 2.

According to an exemplary embodiment of the present invention, xa5 inFormulae 201 and 202 may be an integer selected from 1 to 4.

According to an exemplary embodiment of the present invention, R₂₀₁ toR₂₀₄ and Q₂₀₁ in Formulae 201 and 202 may each independently be selectedfrom a phenyl group, a biphenyl group, a terphenyl group, a pentalenylgroup, an indenyl group, a naphthyl group, an azulenyl group, aheptalenyl group, an indacenyl group, an acenaphthyl group, a fluorenylgroup, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group; and

-   -   phenyl group, a biphenyl group, a terphenyl group, a pentalenyl        group, an indenyl group, a naphthyl group, an azulenyl group, a        heptalenyl group, an indacenyl group, an acenaphthyl group, a        fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl        group, a dibenzofluorenyl group, a phenalenyl group, a        phenanthrenyl group, an anthracenyl group, a fluoranthenyl        group, a triphenylenyl group, a pyrenyl group, a chrysenyl        group, a naphthacenyl group, a picenyl group, a perylenyl group,        a pentaphenyl group, a hexacenyl group, a pentacenyl group, a        rubicenyl group, a coronenyl group, an ovalenyl group, a        thiophenyl group, a furanyl group, a carbazolyl group, an        indolyl group, an isoindolyl group, a benzofuranyl group, a        benzothiophenyl group, a dibenzofuranyl group, a        dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl        group, each substituted with at least one selected from        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a        cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cyclopentenyl group, a cyclohexenyl group, a phenyl group, a        biphenyl group, a terphenyl group, a phenyl group substituted        with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a        pentalenyl group, an indenyl group, a naphthyl group, an        azulenyl group, a heptalenyl group, an indacenyl group, an        acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,        a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl        group, a phenanthrenyl group, an anthracenyl group, a        fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a        chrysenyl group, a naphthacenyl group, a picenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a rubicenyl group, a coronenyl group, an        ovalenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may be the same as described herein.

According to one or more exemplary embodiments of the present invention,at least one selected from R₂₀₁ to R₂₀₃ in Formula 201 may be selectedfrom:

-   -   a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl        group, a dibenzofuranyl group, and a dibenzothiophenyl group;        and    -   a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl        group, a dibenzofuranyl group, and a dibenzothiophenyl group,        each substituted with at least one selected from deuterium, —F,        —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an        amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀        alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a        cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a        cyclohexenyl group, a phenyl group, a biphenyl group, a        terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkyl        group, a phenyl group substituted with —F, a naphthyl group, a        fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group,        a dibenzofuranyl group, and a dibenzothiophenyl group;        however, exemplary embodiments of the present invention are not        limited thereto.

According to an exemplary embodiment of the present invention, inFormula 202, R₂₀₁ and R₂₀₂ may be bound via a single bond, and/or R₂₀₃and R₂₀₄ may be chemically bonded to each other via a single bond.

According to one or more exemplary embodiments of the present invention,at least one of R₂₀₁ to R₂₀₄ in Formula 202 may be selected from:

-   -   a carbazolyl group; and    -   a carbazolyl group substituted with at least one selected from        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a        cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cyclopentenyl group, a cyclohexenyl group, a phenyl group, a        biphenyl group, a terphenyl group, a phenyl group substituted        with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a        naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, a        carbazolyl group, a dibenzofuranyl group, and a        dibenzothiophenyl group;        however, exemplary embodiments of the present invention are not        limited thereto.

The compound represented by Formula 201 may be represented by Formula201A:

The compound represented by Formula 201 may be represented by Formula201A(1); however, exemplary embodiments of the present invention are notlimited thereto:

The compound represented by Formula 201 may be represented by Formula201A-1; however, exemplary embodiments of the present invention are notlimited thereto:

The compound represented by Formula 202 may be represented by Formula202A; however, exemplary embodiments of the present invention are notlimited thereto:

The compound represented by Formula 202 may be represented by Formula202A-1; however, exemplary embodiments of the present invention are notlimited thereto:

In Formulae 201A, 201A(1), 201A-1, 202A, and 202A-1:

-   -   L₂₀₁ to L₂₀₃, xa1 to xa3, xa5, and R₂₀₂ to R₂₀₄ may be the same        as described herein;    -   R₂₁₁ and R₂₁₂ may be the same as R₂₀₃ as described herein; and    -   R₂₁₃ to R₂₁₇ may each independently be selected from hydrogen,        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a        cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cyclopentenyl group, a cyclohexenyl group, a phenyl group, a        biphenyl group, a terphenyl group, a phenyl group substituted        with a C₁-C₁₀ alkyl group, a phenyl group substituted with —F, a        pentalenyl group, an indenyl group, a naphthyl group, an        azulenyl group, a heptalenyl group, an indacenyl group, an        acenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group,        a benzofluorenyl group, a dibenzofluorenyl group, a phenalenyl        group, a phenanthrenyl group, an anthracenyl group, a        fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a        chrysenyl group, a naphthacenyl group, a picenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a rubicenyl group, a coronenyl group, an        ovalenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl        group.

The hole transport region may include at least one compound selectedfrom Compounds HT1 to HT39; however, exemplary embodiments of thepresent invention are not limited thereto:

The thickness of the hole transport region may be in a range from about100 Å to about 10,000 Å, for example, from about 100 Å to about 1,000 Å.When the hole transport region includes at least one selected from ahole injection layer and a hole transport layer, the thickness of thehole injection layer may be in a range from about 100 Å to about 9,000Å, for example, from about 100 Å to about 1,000 Å, and the thickness ofthe hole transport layer may be in a range from about 50 Å to about2,000 Å, for example, from about 100 Å to about 1500 Å. When thethicknesses of the hole transport region, the hole injection layer, andthe hole transport layer are within any of these ranges, satisfactoryhole transporting characteristics may be obtained without a substantialincrease in driving voltage.

The emission auxiliary layer may increase the light-emission efficiencyby compensating for an optical resonance distance depending on thewavelength of light emitted by an emission layer. The electron blockinglayer may decrease or prevent the flow of electrons from an electrontransport region. The emission auxiliary layer and the electron blockinglayer may include materials as described herein.

The hole transport region may include a charge-generation material,which may increase conductive properties of the hole transport region.The charge-generation material may be substantially homogeneously ornon-homogeneously dispersed in the hole transport region.

The charge-generation material may be, for example, a p-dopant.

According to an exemplary embodiment of the present invention, thep-dopant may have a lowest unoccupied molecular orbital (LUMO) level ofabout −3.5 eV or less.

The p-dopant may include at least one selected from a quinonederivative, a metal oxide, and a cyano group-containing compound;however, exemplary embodiments of the present invention are not limitedthereto.

For example, the p-dopant may include at least one selected from:

-   -   a quinone derivative, such as tetracyanoquinodimethane (TCNQ)        and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane        (F4-TCNQ);    -   a metal oxide, such as tungsten oxide or molybdenum oxide;    -   1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN); and    -   a compound represented by Formula 221; however, exemplary        embodiments of the present invention are not limited thereto:

In Formula 221:

-   -   R₂₂₁ to R₂₂₃ may each independently be selected from a        substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a        substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a        substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or        unsubstituted C₁-C₆₀ heteroaryl group, a substituted or        unsubstituted monovalent non-aromatic condensed polycyclic        group, and a substituted or unsubstituted monovalent        non-aromatic condensed heteropolycyclic group, provided that at        least one selected from R₂₂₁ to R₂₂₃ may include at least one        substituent selected from a cyano group, —F, —Cl, —Br, —I, a        C₁-C₂₀ alkyl group substituted with —F, a C₁-C₂₀ alkyl group        substituted with —Cl, a C₁-C₂₀ alkyl group substituted with —Br,        and a C₁-C₂₀ alkyl group substituted with —I.

When the organic light-emitting device 10 is a full color organiclight-emitting device, the emission layer may be patterned into a redemission layer, a green emission layer, and a blue emission layer,according to a sub-pixel. According to an exemplary embodiment of thepresent invention, the emission layer may have a stacked structure. Thestacked structure may include two or more layers selected from a redemission layer, a green emission layer, or a blue emission layer. Thetwo or more layers may be in direct contact with each other.Alternatively, the two or more layers may be separated from each other.According to an exemplary embodiment of the present invention, theemission layer may include two or more materials. The two or morematerials may include a red-light emission material, a green-lightemission material, or a blue-light emission material. The two or morematerials may be mixed with each other in a single layer. The two ormore materials mixed with each other in the single layer may emit whitelight.

The emission layer may include a host and a dopant. The dopant mayinclude at least one of a phosphorescent dopant and a fluorescentdopant.

An amount of the dopant in the emission layer may be in a range fromabout 0.01 parts by weight to about 15 parts by weight based on 100parts by weight of the host; however, exemplary embodiments of thepresent invention are not limited thereto.

The thickness of the emission layer may be in a range from about 100 Åto about 1,000 Å, for example, from about 200 Å to about 600 Å. When thethickness of the emission layer is within any of these ranges, increasedlight-emission characteristics may be obtained without a substantialincrease in driving voltage.

The host may include the first compound and the second compound. Forexample, the host may include the first compound represented by one ofFormulae 1-1 to 1-4 and the second compound represented by Formulae 2a-1to 2a-4, 2b-1 to 2b-6, and 2c-1.

The weight ratio of the first compound to the second compound may be ina range from about 10:90 to about 90:10, for example, from about 30:70to about 70:30. According to an exemplary embodiment of the presentinvention, the weight ratio of the first compound to the second compoundmay be about 30:70; however, exemplary embodiments of the presentinvention are not limited thereto. When the weight ratio of the firstcompound to the second compound is within any of these ranges, thehole-electron transport balance in the emission layer may be achieved.

According to an exemplary embodiment of the present invention, the hostmay include a compound represented by Formula 301:[Ar₃₀₁]_(xb11)-[(L₃₀₁)_(xb1)-R₃₀₁]_(xb21)  [Formula 301]

In Formula 301:

Ar₃₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group;

-   -   xb11 may be an integer selected from 1 to 3;    -   L₃₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀        cycloalkylene group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀        cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkenylene group, a substituted or unsubstituted        C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀        heteroarylene group, a substituted or unsubstituted divalent        non-aromatic condensed polycyclic group, and a substituted or        unsubstituted divalent non-aromatic condensed heteropolycyclic        group;    -   xb1 may be an integer selected from 0 to 5;    -   R₃₀₁ may be selected from deuterium, —F, —Cl, —Br, —I, a        hydroxyl group, a cyano group, a nitro group, an amidino group,        a hydrazino group, a hydrazono group, a substituted or        unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted        C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀        alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy        group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a        substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a        substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or        unsubstituted C₆-C₆₀ aryloxy group, a substituted or        unsubstituted C₆-C₆₀ arylthio group, a substituted or        unsubstituted C₁-C₆₀ heteroaryl group, a substituted or        unsubstituted monovalent non-aromatic condensed polycyclic        group, a substituted or unsubstituted monovalent non-aromatic        condensed heteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃),        —N(Q₃₀₁)(Q₃₀₂), —B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and        —P(═O)(Q₃₀₁)(Q₃₀₂); and    -   xb21 may be an integer selected from 1 to 5.

Q₃₀₁ to Q₃₀₃ may each independently be selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, or a naphthyl group; however, exemplary embodiments ofthe present invention are not limited thereto.

According to an exemplary embodiment of the present invention, Ar₃₀₁ inFormula 301 may be selected from:

-   -   a naphthalene group, a fluorene group, a spiro-bifluorene group,        a benzofluorene group, a dibenzofluorene group, a phenalene        group, a phenanthrene group, an anthracene group, a fluoranthene        group, a triphenylene group, a pyrene group, a chrysene group, a        naphthacene group, a picene group, a perylene group, a        pentaphene group, an indenoanthracene group, a dibenzofuran        group, and a dibenzothiophene group; and    -   a naphthalene group, a fluorene group, a spiro-bifluorene group,        a benzofluorene group, a dibenzofluorene group, a phenalene        group, a phenanthrene group, an anthracene group, a fluoranthene        group, a triphenylene group, a pyrene group, a chrysene group, a        naphthacene group, a picene group, a perylene group, a        pentaphene group, an indenoanthracene group, a dibenzofuran        group, and a dibenzothiophene group, each substituted with at        least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl        group, a cyano group, a nitro group, an amidino group, a        hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a        C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a        terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),        —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and        —P(═O)(Q₃₁)(Q₃₂),    -   Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀        alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl        group, a terphenyl group, and a naphthyl group; however,        exemplary embodiments of the present invention are not limited        thereto.

When xb11 in Formula 301 is 2 or greater, a plurality of Ar₃₀₁(s) may bechemically bonded to each other via a single bond.

According to one or more exemplary embodiments of the present invention,the compound represented by Formula 301 may be represented by Formula301-1 or 301-2:

In Formulae 301-1 to 301-2:

-   -   A₃₀₁ to A₃₀₄ may each independently be selected from a benzene        group, a naphthalene group, a phenanthrene group, a fluoranthene        group, a triphenylene group, a pyrene group, a chrysene group, a        pyridine group, a pyrimidine group, an indene group, a fluorene        group, a spiro-bifluorene group, a benzofluorene group, a        dibenzofluorene group, an indole group, a carbazole group, a        benzocarbazole group, a dibenzocarbazole group, a furan group, a        benzofuran group, a dibenzofuran group, a naphthofuran group, a        benzonaphthofuran group, a dinaphthofuran group, a thiophene        group, a benzothiophene group, a dibenzothiophene group, a        naphthothiophene group, a benzonaphthothiophene group, and a        dinaphthothiophene group;    -   X₃₀₁ may be selected from O, S, or N-[(L₃₀₄)_(xb4)-R₃₀₄];    -   R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen,        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group        —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂);    -   xb22 and xb23 may each independently be an integer selected from        0 to 2;    -   L₃₀₁, xb1, R₃₀₁, and Q₃₁ to Q₃₃ may be the same as described        herein;    -   L₃₀₂ to L₃₀₄ may be the same as L₃₀₁ as described herein;    -   xb2 to xb4 may be the same as xb1 as described herein; and    -   R₃₀₂ to R₃₀₄ may be each independently the same as R₃₀₁ as        described herein.

According to an exemplary embodiment of the present invention, inFormulae 301, 301-1, and 301-2, L₃₀₁ to L₃₀₄ may each independently beselected from:

-   -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a fluoranthenylene group, a        triphenylenylene group, a pyrenylene group, a chrysenylene        group, a perylenylene group, a pentaphenylene group, a        hexacenylene group, a pentacenylene group, a thiophenylene        group, a furanylene group, a carbazolylene group, an indolylene        group, an isoindolylene group, a benzofuranylene group, a        benzothiophenylene group, a dibenzofuranylene group, a        dibenzothiophenylene group, a benzocarbazolylene group, a        dibenzocarbazolylene group, a dibenzosilolylene group, a        pyridinylene group, an imidazolylene group, a pyrazolylene        group, a thiazolylene group, an isothiazolylene group, an        oxazolylene group, an isoxazolylene group, a thiadiazolylene        group, an oxadiazolylene group, a pyrazinylene group, a        pyrimidinylene group, a pyridazinylene group, a triazinylene        group, a quinolinylene group, an isoquinolinylene group, a        benzoquinolinylene group, a phthalazinylene group, a        naphthyridinylene group, a quinoxalinylene group, a        quinazolinylene group, a cinnolinylene group, a        phenanthridinylene group, an acridinylene group, a        phenanthrolinylene group, a phenazinylene group, a        benzimidazolylene group, an isobenzothiazolylene group, a        benzoxazolylene group, an isobenzoxazolylene group, a        triazolylene group, a tetrazolylene group, an        imidazopyridinylene group, an imidazopyrimidinylene group, and        an azacarbazolylene group; and    -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a fluoranthenylene group, a        triphenylenylene group, a pyrenylene group, a chrysenylene        group, a perylenylene group, a pentaphenylene group, a        hexacenylene group, a pentacenylene group, a thiophenylene        group, a furanylene group, a carbazolylene group, an indolylene        group, an isoindolylene group, a benzofuranylene group, a        benzothiophenylene group, a dibenzofuranylene group, a        dibenzothiophenylene group, a benzocarbazolylene group, a        dibenzocarbazolylene group, a dibenzosilolylene group, a        pyridinylene group, an imidazolylene group, a pyrazolylene        group, a thiazolylene group, an isothiazolylene group, an        oxazolylene group, an isoxazolylene group, a thiadiazolylene        group, an oxadiazolylene group, a pyrazinylene group, a        pyrimidinylene group, a pyridazinylene group, a triazinylene        group, a quinolinylene group, an isoquinolinylene group, a        benzoquinolinylene group, a phthalazinylene group, a        naphthyridinylene group, a quinoxalinylene group, a        quinazolinylene group, a cinnolinylene group, a        phenanthridinylene group, an acridinylene group, a        phenanthrolinylene group, a phenazinylene group, a        benzimidazolylene group, an isobenzothiazolylene group, a        benzoxazolylene group, an isobenzoxazolylene group, a        triazolylene group, a tetrazolylene group, an        imidazopyridinylene group, an imidazopyrimidinylene group and an        azacarbazolylene group, each substituted with at least one        selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a        cyano group, a nitro group, an amidino group, a hydrazino group,        a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,        a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl        group, a pyrimidinyl group, a pyridazinyl group, a triazinyl        group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl        group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl        group, a phenanthridinyl group, an acridinyl group, a        phenanthrolinyl group, a phenazinyl group, a benzimidazolyl        group, an isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group, an        azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),        —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may be the same as those described herein.

According to an exemplary embodiment of the present invention, inFormulae 301, 301-1, and 301-2, R₃₀₁ to R₃₀₄ may each independently beselected from:

-   -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl        group, a pyrimidinyl group, a pyridazinyl group, a triazinyl        group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl        group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl        group, a phenanthridinyl group, an acridinyl group, a        phenanthrolinyl group, a phenazinyl group, a benzimidazolyl        group, an isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group, and an        azacarbazolyl group; and    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl        group, a pyrimidinyl group, a pyridazinyl group, a triazinyl        group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl        group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl        group, a phenanthridinyl group, an acridinyl group, a        phenanthrolinyl group, a phenazinyl group, a benzimidazolyl        group, an isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group, and an        azacarbazolyl group, each substituted with at least one selected        from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a        phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl        group, a pyrimidinyl group, a pyridazinyl group, a triazinyl        group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl        group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl        group, a phenanthridinyl group, an acridinyl group, a        phenanthrolinyl group, a phenazinyl group, a benzimidazolyl        group, an isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group, an        azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),        —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may be the same as described herein.

According to an exemplary embodiment of the present invention, the hostmay include an alkaline earth-metal complex. For example, the host mayinclude a Be complex (e.g., Compound H55), an Mg complex, or a Zncomplex.

The host may include at least one selected from9,10-Di(2-naphthyl)anthracene (ADN),2-Methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN),9,10-di-(2-naphthyl)-2-t-butyl-anthracene (TBADN),4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene(mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), and Compounds H1 to H55;however, exemplary embodiments of the present invention are not limitedthereto:

The phosphorescent dopant may include an organometallic complexrepresented by Formula 401:M(L₄₀₁)_(xc1)(L₄₀₂)_(xc2)  [Formula 401]

[Formula 402]

In Formulae 401 and 402:

-   -   M may be selected from iridium (Ir), platinum (Pt), palladium        (Pd), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf),        europium (Eu), terbium (Tb), rhodium (Rh), and thulium (Tm);    -   L₄₀₁ may be selected from ligands represented by Formula 402.        xc1 may be an integer selected from 1 to 3. When xc1 is 2 or        greater, at least two L₄₀₁(s) may be the same as or different        from each other,    -   L₄₀₂ may be an organic ligand. xc2 may be an integer selected        from 0 to 4. When xc2 is 2 or greater, at least two L₄₀₂(s) may        be the same as or different from each other;    -   X₄₀₁ to X₄₀₄ may each independently be selected from nitrogen or        carbon;    -   X₄₀₁ and X₄₀₃ may be chemically bonded to each other via a        single bond or a double bond;    -   X₄₀₂ and X₄₀₄ may be chemically bonded to each other via a        single bond or a double bond;    -   A₄₀₁ and A₄₀₂ may each independently be selected from a C₅-C₆₀        carbocyclic group or a C₁-C₆₀ heterocyclic group;    -   X₄₀₅ may be selected from a single bond, *—O—*′, *—S—*′,        *—C(═O)—*′, *—N(Q₄₁₁)-′, *—C(Q₄₁₁)(Q₄₁₂)-*′,        *—C(Q₄₁₁)═C(Q₄₁₂)-*′, *—C(Q₄₁₁)=*′, or *—C═*′, wherein Q₄₁₁ and        Q₄₁₂ may each independently be hydrogen, deuterium, a C₁-C₂₀        alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl        group, a terphenyl group, or a naphthyl group;    -   X₄₀₆ may be selected from a single bond, O, and S;    -   R₄₀₁ and R₄₀₂ may each independently be selected from hydrogen,        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a substituted or unsubstituted C₁-C₂₀ alkyl group, a        substituted or unsubstituted C₁-C₂₀ alkoxy group, a substituted        or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or        unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or        unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or        unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or        unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted        C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀        arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroaryl        group, a substituted or unsubstituted monovalent non-aromatic        condensed polycyclic group and a substituted or unsubstituted        monovalent non-aromatic condensed heteropolycyclic group,        —Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂),        —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), and —P(═O)(Q₄₀₁)(Q₄₀₂), wherein        Q₄₀₁ to Q₄₀₃ may each independently be selected from a C₁-C₁₀        alkyl group, a C₁-C₁₀ alkoxy group, a C₆-C₂₀ aryl group, and a        C₁-C₂₀ heteroaryl group;    -   xc11 and xc12 may each independently be an integer selected from        0 to 10; and    -   * and *′ in Formula 402 may each indicate a binding site to M in        Formula 401.

According to an exemplary embodiment of the present invention, inFormula 402, A₄₀₁ and A₄₀₂ may each independently be selected from abenzene group, a naphthalene group, a fluorene group, a spiro-bifluorenegroup, an indene group, a pyrrole group, a thiophene group, a furangroup, an imidazole group, a pyrazole group, a thiazole group, anisothiazole group, an oxazole group, an isoxazole group, a pyridinegroup, a pyrazine group, a pyrimidine group, a pyridazine group, aquinoline group, an isoquinoline group, a benzoquinoline group, aquinoxaline group, a quinazoline group, a carbazole group, abenzimidazole group, a benzofuran group, a benzothiophene group, anisobenzothiophene group, a benzoxazole group, an isobenzoxazole group, atriazole group, a tetrazole group, an oxadiazole group, a triazinegroup, a dibenzofuran group, or a dibenzothiophene group.

According to one or more exemplary embodiments of the present invention,in Formula 402, X₄₀₁ may be nitrogen and X₄₀₂ may be carbon.Alternatively, X₄₀₁ and X₄₀₂ may both be nitrogen.

According to one or more exemplary embodiments of the present invention,in Formula 402, R₄₀₂ and R₄₀₁ may each independently be selected from:

-   -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy        group;    -   a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted        with at least one selected from deuterium, —F, —Cl, —Br, —I, a        hydroxyl group, a cyano group, a nitro group, an amidino group,        a hydrazino group, a hydrazono group, a phenyl group, a naphthyl        group, a cyclopentyl group, a cyclohexyl group, an adamantyl        group, a norbornanyl group, and a norbornenyl group;    -   a cyclopentyl group, a cyclohexyl group, an adamantyl group, a        norbornanyl group, a norbornenyl group, a phenyl group, a        biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl        group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl        group, a pyridazinyl group, a triazinyl group, a quinolinyl        group, an isoquinolinyl group, a quinoxalinyl group, a        quinazolinyl group, a carbazolyl group, a dibenzofuranyl group,        and a dibenzothiophenyl group;    -   a cyclopentyl group, a cyclohexyl group, an adamantyl group, a        norbornanyl group, a norbornenyl group, a phenyl group, a        biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl        group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl        group, a pyridazinyl group, a triazinyl group, a quinolinyl        group, an isoquinolinyl group, a quinoxalinyl group, a        quinazolinyl group, a carbazolyl group, a dibenzofuranyl group,        and a dibenzothiophenyl group, each substituted with at least        one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,        a cyano group, a nitro group, an amidino group, a hydrazino        group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy        group, a cyclopentyl group, a cyclohexyl group, an adamantyl        group, a norbornanyl group, a norbornenyl group, a phenyl group,        a biphenyl group, a terphenyl group, a naphthyl group, a        fluorenyl group, a pyridinyl group, a pyrazinyl group, a        pyrimidinyl group, a pyridazinyl group, a triazinyl group, a        quinolinyl group, an isoquinolinyl group, a quinoxalinyl group,        a quinazolinyl group, a carbazolyl group, a dibenzofuranyl        group, and a dibenzothiophenyl group; and    -   —Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂),        —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), and —P(═O)(Q₄₀₁)(Q₄₀₂).

Q₄₀₁ to Q₄₀₃ may each independently be selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, or anaphthyl group; however, exemplary embodiments of the present inventionare not limited thereto.

According to one or more exemplary embodiments of the present invention,when xc1 in Formula 401 is 2 or greater, two A₄₀₁(s) of a plurality ofL₄₀₁(s) may be bound via X₄₀₇ as a linking group. Alternatively, twoA₄₀₂(s) may be bound via X₄₀₈ as a linking group (see, e.g., CompoundsPD1 to PD4 and PD7 below). X₄₀₇ and X₄₀₈ may each independently beselected from a single bond, *—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q₄₁₃)-*′,*—C(Q₄₁₃)(Q₄₁₄)-*′, or *—C(Q₄₁₃)=C(Q₄₁₄)-*′. Q₄₁₃ and Q₄₁₄ may eachindependently be hydrogen, deuterium, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or anaphthyl group; however, exemplary embodiments of the present inventionare not limited thereto.

L₄₀₂ in Formula 401 may be selected from any suitable monovalent,divalent, and trivalent organic ligand. For example, L₄₀₂ may beselected from halogen, diketone (e.g., acetylacetonate), a carboxylicacid (e.g., picolinate), —C(═O), isonitrile, —CN, andphosphorus-containing material (e.g., phosphine or phosphite); however,exemplary embodiments of the present invention are not limited thereto.

According to an exemplary embodiment of the present invention, thephosphorescent dopant may include, for example, at least one selectedfrom Compounds PD1 to PD26; however, exemplary embodiments of thepresent invention are not limited thereto:

The fluorescent dopant may include an arylamine compound or astyrylamine compound.

The fluorescent dopant may include a compound represented by Formula501:

In Formula 501:

-   -   Ar₅₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic        group or a substituted or unsubstituted C₁-C₆₀ heterocyclic        group;    -   L₅₀₁ to L₅₀₃ may each independently be selected from a        substituted or unsubstituted C₃-C₁₀ cycloalkylene group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkylene group, a        substituted or unsubstituted C₃-C₁₀ cycloalkenylene group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkenylene group,        a substituted or unsubstituted C₆-C₆₀ arylene group, a        substituted or unsubstituted C₁-C₆₀ heteroarylene group, a        substituted or unsubstituted divalent non-aromatic condensed        polycyclic group, and a substituted or unsubstituted divalent        non-aromatic condensed heteropolycyclic group;    -   xd1 to xd3 may each independently be an integer selected from 0        to 3;    -   R₅₀₁ and R₅₀₂ may each independently be selected from a        substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a        substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a        substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a        substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or        unsubstituted C₆-C₆₀ aryloxy group, a substituted or        unsubstituted C₆-C₆₀ arylthio group, a substituted or        unsubstituted C₁-C₆₀ heteroaryl group, a substituted or        unsubstituted monovalent non-aromatic condensed polycyclic        group, and a substituted or unsubstituted monovalent        non-aromatic condensed heteropolycyclic group; and    -   xd4 may be an integer selected from 1 to 6.

According to an exemplary embodiment of the present invention, Ar_(5o1)in Formula 501 may be selected from:

-   -   a naphthalene group, a heptalene group, a fluorene group, a        spiro-bifluorene group, a benzofluorene group, a dibenzofluorene        group, a phenalene group, a phenanthrene group, an anthracene        group, a fluoranthene group, a triphenylene group, a pyrene        group, a chrysene group, a naphthacene group, a picene group, a        perylene group, a pentaphene group, an indenoanthracene group,        and an indenophenanthrene group; or    -   a naphthalene group, a heptalene group, a fluorene group, a        spiro-bifluorene group, a benzofluorene group, a dibenzofluorene        group, a phenalene group, a phenanthrene group, an anthracene        group, a fluoranthene group, a triphenylene group, a pyrene        group, a chrysene group, a naphthacene group, a picene group, a        perylene group, a pentaphene group, an indenoanthracene group,        and an indenophenanthrene group, each substituted with at least        one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,        a cyano group, a nitro group, an amidino group, a hydrazino        group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy        group, a phenyl group, a biphenyl group, a terphenyl group, and        a naphthyl group.

According to an exemplary embodiment of the present invention, L₅₀₁ toL₅₀₃ in Formula 501 may each independently be selected from:

-   -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a fluoranthenylene group, a        triphenylenylene group, a pyrenylene group, a chrysenylene        group, a perylenylene group, a pentaphenylene group, a        hexacenylene group, a pentacenylene group, a thiophenylene        group, a furanylene group, a carbazolylene group, an indolylene        group, an isoindolylene group, a benzofuranylene group, a        benzothiophenylene group, a dibenzofuranylene group, a        dibenzothiophenylene group, a benzocarbazolylene group, a        dibenzocarbazolylene group, a dibenzosilolylene group, and a        pyridinylene group; and    -   a phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a fluoranthenylene group, a        triphenylenylene group, a pyrenylene group, a chrysenylene        group, a perylenylene group, a pentaphenylene group, a        hexacenylene group, a pentacenylene group, a thiophenylene        group, a furanylene group, a carbazolylene group, an indolylene        group, an isoindolylene group, a benzofuranylene group, a        benzothiophenylene group, a dibenzofuranylene group, a        dibenzothiophenylene group, a benzocarbazolylene group, a        dibenzocarbazolylene group, a dibenzosilolylene group, and a        pyridinylene group, each substituted with at least one selected        from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a        phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl        group.

According to an exemplary embodiment of the present invention, inFormula 501, R₅₀₂ and R₅₀₁ may each independently be selected from:

-   -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl        group; and    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, and a pyridinyl        group, each substituted with at least one selected from        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, a naphthyl group, a        fluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl        group, a dibenzofluorenyl group, a phenanthrenyl group, an        anthracenyl group, a fluoranthenyl group, a triphenylenyl group,        a pyrenyl group, a chrysenyl group, a perylenyl group, a        pentaphenyl group, a hexacenyl group, a pentacenyl group, a        thiophenyl group, a furanyl group, a carbazolyl group, an        indolyl group, an isoindolyl group, a benzofuranyl group, a        benzothiophenyl group, a dibenzofuranyl group, a        dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, and —Si(Q₃₁)(Q₃₂)(Q₃₃).

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

According to one or more exemplary embodiments of the present invention,xd4 in Formula 501 may be 2; however, exemplary embodiments of thepresent invention are not limited thereto.

According to one or more exemplary embodiments of the present invention,the fluorescent dopant may be selected from Compounds FD1 to FD22:

According to one or more exemplary embodiments of the present invention,the fluorescent dopant may be selected from the following compounds;however, exemplary embodiments of the present invention are not limitedthereto:

The electron transport region may have a single-layered structureincluding a single layer including a single material. The electrontransport region may have a single-layered structure including a singlelayer including a plurality of different materials. The electrontransport region may have a multi-layered structure having a pluralityof layers each including a plurality of different materials.

The electron transport region may include at least one selected from abuffer layer, a hole blocking layer, an electron control layer, anelectron transport layer, and an electron injection layer; however,exemplary embodiments of the present invention are not limited thereto.

For example, the electron transport region may have an electrontransport layer/electron injection layer structure, a hole blockinglayer/electron transport layer/electron injection layer structure, anelectron control layer/electron transport layer/electron injection layerstructure, or a buffer layer/electron transport layer/electron injectionlayer structure. For each structure, the layers may be sequentiallystacked on an emission layer. However, exemplary embodiments of thestructure of the electron transport region are not limited thereto.

The electron transport region (e.g., a buffer layer, a hole blockinglayer, an electron control layer, or an electron transport layerdisposed on the electron transport region) may include a metal-freecompound including at least one π electron-depleted nitrogen-containingring.

The term “π electron-depleted nitrogen-containing ring” as used hereinmay indicate a C₁-C₆₀ heterocyclic group having at least one *—N═*′moiety as a ring-forming moiety.

For example, the π electron-depleted nitrogen-containing ring may be a5-membered to 7-membered heteromonocyclic group having at least one*—N═*′ moiety. The π electron-depleted nitrogen-containing ring may be aheteropolycyclic group in which two or more 5-membered to 7-memberedheteromonocyclic groups each having at least one *—N═*′ moiety arecondensed. The π electron-depleted nitrogen-containing ring may be aheteropolycyclic group in which at least one 5-membered to 7-memberedheteromonocyclic group having at least one *—N═*′ moiety is condensedwith at least one C₅-C₆₀ carbocyclic group.

Examples of the π electron-depleted nitrogen-containing ring may includean imidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, anisoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, anindazole, a purine, a quinoline, an isoquinoline, a benzoquinoline, aphthalazine, a naphthyridine, a quinoxaline, a quinazoline, a cinnoline,a phenanthridine, an acridine, a phenanthroline, a phenazine, abenzimidazole, an isobenzothiazole, a benzoxazole, an isobenzoxazole, atriazole, a tetrazole, an oxadiazole, a triazine, thiadiazol, animidazopyridine, an imidazopyrimidine, or an azacarbazole; however,exemplary embodiments of the present invention are not limited thereto.

For example, the electron transport region may include a compoundrepresented by Formula 601:[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21)  [Formula 601]

In Formula 601:

-   -   Ar₆₀₁ may be selected from a substituted or unsubstituted C₅-C₆₀        carbocyclic group and a substituted or unsubstituted C₁-C₆₀        heterocyclic group;    -   xe11 may be an integer selected from 1 to 3;    -   L₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀        cycloalkylene group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀        cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkenylene group, a substituted or unsubstituted        C₆-C₆₀ arylene group, a substituted or unsubstituted C₁-C₆₀        heteroarylene group, a substituted or unsubstituted divalent        non-aromatic condensed polycyclic group, and a substituted or        unsubstituted divalent non-aromatic condensed heteropolycyclic        group;    -   xe1 may be an integer selected from 0 to 5;    -   R₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀        cycloalkyl group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀        cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀        heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀        aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group,        a substituted or unsubstituted C₆-C₆₀ arylthio group, a        substituted or unsubstituted C₁-C₆₀ heteroaryl group, a        substituted or unsubstituted monovalent non-aromatic condensed        polycyclic group, a substituted or unsubstituted monovalent        non-aromatic condensed heteropolycyclic group,        —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁), —S(═O)₂(Q₆₀₁), and        —P(═O)(Q₆₀₁)(Q₆₀₂);    -   Q₆₀₁ to Q₆₀₃ may each independently be a C₁-C₁₀ alkyl group, a        C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a        terphenyl group, or a naphthyl group; and    -   xe21 may be an integer selected from 1 to 5.

According to an exemplary embodiment of the present invention, at leastone of Ar₆₀₁(s) in the number of xe11 and/or at least one of R₆₀₁(s) inthe number xe21 may include the π electron-depleted nitrogen-containingring.

According to one or more exemplary embodiments of the present invention,Ar₆₀₁ in Formula 601 may be selected from:

-   -   a benzene group, a naphthalene group, a fluorene group, a        spiro-bifluorene group, a benzofluorene group, a dibenzofluorene        group, a phenalene group, a phenanthrene group, an anthracene        group, a fluoranthene group, a triphenylene group, a pyrene        group, a chrysene group, naphthacene group, a picene group, a        perylene group, a pentaphene group, an indenoanthracene group, a        dibenzofuran group, a dibenzothiophene group, a carbazole group,        an imidazole group, a pyrazole group, a thiazole group, an        isothiazole group, an oxazole group, an isoxazole group, a        pyridine group, a pyrazine group, a pyrimidine group, a        pyridazine group, an indazole group, a purine group, a quinoline        group, an isoquinoline group, a benzoquinoline group, a        phthalazine group, a naphthyridine group, a quinoxaline group, a        quinazoline group, a cinnoline group, a phenanthridine group, an        acridine group, a phenanthroline group, a phenazine group, a        benzimidazole group, an iso-benzothiazole group, a benzoxazole        group, an isobenzoxazole group, a triazole group, a tetrazole        group, an oxadiazole group, a triazine group, thiadiazol group,        an imidazopyridine group, an imidazopyrimidine group, or an        azacarbazole group; or    -   a benzene group, a naphthalene group, a fluorene group, a        spiro-bifluorene group, a benzofluorene group, a dibenzofluorene        group, a phenalene group, a phenanthrene group, an anthracene        group, a fluoranthene group, a triphenylene group, a pyrene        group, a chrysene group, a naphthacene group, a picene group, a        perylene group, a pentaphene group, an indenoanthracene group, a        dibenzofuran group, a dibenzothiophene group, a carbazole group,        an imidazole group, a pyrazole group, a thiazole group, an        isothiazole group, an oxazole group, an isoxazole group, a        pyridine group, a pyrazine group, a pyrimidine group, a        pyridazine group, an indazole group, a purine group, a quinoline        group, an isoquinoline group, a benzoquinoline group, a        phthalazine group, a naphthyridine group, a quinoxaline group, a        quinazoline group, a cinnoline group, a phenanthridine group, an        acridine group, a phenanthroline group, a phenazine group, a        benzimidazole group, an isobenzothiazole group, a benzoxazole        group, an isobenzoxazole group, a triazole group, a tetrazole        group, an oxadiazole group, a triazine group, a thiadiazol        group, an imidazopyridine group, an imidazopyrimidine group, and        an azacarbazole group, each substituted with at least one        selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a        cyano group, a nitro group, an amidino group, a hydrazino group,        a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,        a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀ alkyl group,a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

When xe11 in Formula 601 is 2 or greater, at least two Ar₆₀₁(s) may bechemically bonded to each other via a single bond.

According to an exemplary embodiment of the present invention, Ar₆₀₁ inFormula 601 may be an anthracene group.

According to an exemplary embodiment of the present invention, thecompound represented by Formula 601 may be represented by Formula 601-1:

In Formula 601-1:

X₆₁₄ may be selected from N or C(R₆₁₄), X₆₁₅ may be selected from N orC(R₆₁₅), X₆₁₆ may be selected from N or C(R₆₁₆), and at least one ofX₆₁₄ to X₆₁₆ may be N;

-   -   L₆₁₁ to L₆₁₃ may be the same as L₆₀₁ as described herein;    -   xe611 to xe613 may be the same as xe1 as described herein;    -   R₆₁₁ to R₆₁₃ may be the same as R₆₀₁ as described herein; and    -   R₆₁₄ to R₆₁₆ may each independently be selected from hydrogen,        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazino group, a hydrazono        group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl        group, a biphenyl group, a terphenyl group, and a naphthyl        group.

According to an exemplary embodiment of the present invention, L₆₀₁ andL₆₁₁ to L₆₁₃ in Formulae 601 and 601-1 may each independently beselected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazoiylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group; and

-   -   phenylene group, a naphthylene group, a fluorenylene group, a        spiro-bifluorenylene group, a benzofluorenylene group, a        dibenzofluorenylene group, a phenanthrenylene group, an        anthracenylene group, a fluoranthenylene group, a        triphenylenylene group, a pyrenylene group, a chrysenylene        group, a perylenylene group, a pentaphenylene group, a        hexacenylene group, a pentacenylene group, a thiophenylene        group, a furanylene group, a carbazolylene group, an indolylene        group, an isoindolylene group, a benzofuranylene group, a        benzothiophenylene group, a dibenzofuranylene group, a        dibenzothiophenylene group, a benzocarbazolylene group, a        dibenzocarbazolylene group, a dibenzosilolylene group, a        pyridinylene group, an imidazolylene group, a pyrazolylene        group, a thiazolylene group, an isothiazolylene group, an        oxazolylene group, an isoxazolylene group, a thiadiazolylene        group, an oxadiazolylene group, a pyrazinylene group, a        pyrimidinylene group, a pyridazinylene group, a triazinylene        group, a quinolinylene group, an isoquinolinylene group, a        benzoquinolinylene group, a phthalazinylene group, a        naphthyridinylene group, a quinoxalinylene group, a        quinazolinylene group, a cinnolinylene group, a        phenanthridinylene group, an acridinylene group, a        phenanthrolinylene group, a phenazinylene group, a        benzimidazolylene group, an isobenzothiazolylene group, a        benzoxazolylene group, an isobenzoxazolylene group, a        triazolylene group, a tetrazolylene group, an        imidazopyridinylene group, an imidazopyrimidinylene group, and        an azacarbazolylene group, each substituted with at least one        selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a        cyano group, a nitro group, an amidino group, a hydrazino group,        a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,        a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl        group, a pyrimidinyl group, a pyridazinyl group, a triazinyl        group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl        group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl        group, a phenanthridinyl group, an acridinyl group, a        phenanthrolinyl group, a phenazinyl group, a benzimidazolyl        group, an isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group, and an        azacarbazolyl group; however, exemplary embodiments of the        present invention are not limited thereto.

According to an exemplary embodiment of the present invention, xe1 andxe611 to xe613 in Formulae 601 and 601-1 may each independently be aninteger selected from 0 to 2.

According to an exemplary embodiment of the present invention, R₆₀₁ toR₆₁₁ and R₆₁₃ in Formulae 601 and 601-1 may each independently beselected from:

-   -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl        group, a pyrimidinyl group, a pyridazinyl group, a triazinyl        group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl        group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl        group, a phenanthridinyl group, an acridinyl group, a        phenanthrolinyl group, a phenazinyl group, a benzimidazolyl        group, an isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group, and an        azacarbazolyl group; and    -   a phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl        group, a pyrimidinyl group, a pyridazinyl group, a triazinyl        group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl        group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl        group, a phenanthridinyl group, an acridinyl group, a        phenanthrolinyl group, a phenazinyl group, a benzimidazolyl        group, an isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group, and an        azacarbazolyl group, each substituted with at least one selected        from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a        phenyl group, a biphenyl group, a terphenyl group, a naphthyl        group, a fluorenyl group, a spiro-bifluorenyl group, a        benzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl        group, an anthracenyl group, a fluoranthenyl group, a        triphenylenyl group, a pyrenyl group, a chrysenyl group, a        perylenyl group, a pentaphenyl group, a hexacenyl group, a        pentacenyl group, a thiophenyl group, a furanyl group, a        carbazolyl group, an indolyl group, an isoindolyl group, a        benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl        group, a dibenzothiophenyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl        group, an imidazolyl group, a pyrazolyl group, a thiazolyl        group, an isothiazolyl group, an oxazolyl group, an isoxazolyl        group, a thiadiazolyl group, an oxadiazolyl group, a pyrazinyl        group, a pyrimidinyl group, a pyridazinyl group, a triazinyl        group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a phthalazinyl group, a naphthyridinyl        group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl        group, a phenanthridinyl group, an acridinyl group, a        phenanthrolinyl group, a phenazinyl group, a benzimidazolyl        group, an isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group, and an        azacarbazolyl group; and    -   —S(═O)₂(Q₆₀₁) and —P(═O)(Q₆₀₁)(Q₆₀₂).

Q₆₀₁ and Q₆₀₂ may be the same as described herein.

The electron transport region may include at least one compound selectedfrom Compounds ET1 to ET36; however, exemplary embodiments of thepresent invention are not limited thereto:

According to one or more exemplary embodiments of the present invention,the electron transport region may include at least one selected from2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP),4,7-dphenyl-1,10-phenanthroline (Bphen), Alq₃, BAlq,3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ), and NTAZ:

Thicknesses of the buffer layer, the hole blocking layer, and theelectron control layer may each be in a range from about 20 Å to about1,000 Å, for example, from about 30 Å to about 300 Å. When thethicknesses of the buffer layer, the hole blocking layer, and theelectron control layer are each within any of these ranges, the electrontransport region may have increased electron blocking characteristics orelectron control characteristics without a substantial increase indriving voltage.

The thickness of the electron transport layer may be in a range fromabout 100 Å to about 1,000 Å, for example, from about 150 Å to about 500Å. When the thickness of the electron transport layer is within any ofthese ranges, the electron transport layer may have satisfactoryelectron transport characteristics without a substantial increase indriving voltage.

The electron transport region (e.g., the electron transport layer in theelectron transport region) may include a material including metal.

The material including metal may include at least one of an alkali metalcomplex or an alkaline earth-metal complex. The alkali metal complex mayinclude a metal ion selected from a lithium (Li) ion, a sodium (Na) ion,a potassium (K) ion, a rubidium (Rb) ion, and a caesium (Cs) ion. Thealkaline earth-metal complex may include a metal ion selected from aberyllium (Be) ion, a magnesium (Mg) ion, a calcium (Ca) ion, astrontium (Sr) ion, and a barium (Ba) ion. A ligand coordinated with themetal ion of the alkali metal complex or the alkaline earth-metalcomplex may be selected from a hydroxyquinoline, a hydroxyisoquinoline,a hydroxybenzoquinoline, a hydroxyacridine, a hydroxyphenanthridine, ahydroxyphenyloxazole, a hydroxyphenylthiazole, a hydroxydiphenyloxadiazole, a hydroxydiphenyl thiadiazole, a hydroxyphenyl pyridine, ahydroxyphenyl benzimidazole, a hydroxyphenyl benzothiazole, abipyridine, a phenanthroline, and a cyclopentadiene; however, exemplaryembodiments of the present invention are not limited thereto.

For example, the material including metal may include a lithium (Li)complex. The lithium (Li) complex may include, for example, CompoundET-D1 (lithium quinolate, LiQ) or ET-D2:

The electron transport region may include an electron injection layer.The electron injection layer may facilitate electron injection from thesecond electrode 190. The electron injection layer may be in directcontact with the second electrode 190.

The electron transport region may have a single-layered structureincluding a single layer including a single material. The electrontransport region may have a single-layered structure including a singlelayer including a plurality of different materials. The electrontransport region may have a multi-layered structure having a pluralityof layers each including a plurality of different materials.

The electron injection layer may include an alkali metal, an alkalineearth-metal, a rare-earth metal, an alkali metal compound, an alkalineearth-metal compound, a rare-earth metal compound, an alkali metalcomplex, an alkaline earth-metal complex, a rare-earth metal complex, orany combination thereof.

The alkali metal may be selected from Li, Na, K, Rb, and Cs. Accordingto an exemplary embodiment of the present invention, the alkali metalmay be Li, Na, or Cs. According to an exemplary embodiment of thepresent invention, the alkali metal may be Li or Cs; however, exemplaryembodiments of the present invention are not limited thereto.

The alkaline earth-metal may be selected from Mg, Ca, Sr, and Ba.

The rare-earth metal may be selected from Sc, Y, Ce, Tb, Yb, and Gd.

The alkali metal compound, the alkaline earth-metal compound, and therare-earth metal compound may be each independently selected from oxidesor halides (e.g., fluorides, chlorides, bromides, or iodines) of thealkaline metal, the alkaline earth-metal, and the rare-earth metal,respectively.

The alkali metal compound may be selected from alkali metal oxides, suchas Li₂O, Cs₂O, or K₂O, and alkali metal halides, such as LiF, NaF, CsF,KF, LiI, NaI, CsI, or KI. According to an exemplary embodiment of thepresent invention, the alkali metal compound may be selected from LiF,Li₂O, NaF, LiI, NaI, CsI, and KI; however, exemplary embodiments of thepresent invention are not limited thereto.

The alkaline earth-metal compound may be selected from alkalineearth-metal compounds, such as BaO, SrO, CaO, Ba_(x)Sr_(1-x)O (0<x<1),or Ba_(x)Ca_(1-x)O (0<x<1). According to an exemplary embodiment of thepresent invention, the alkaline earth-metal compound may be selectedfrom BaO, SrO, and CaO; however, exemplary embodiments of the presentinvention are not limited thereto.

The rare-earth metal compound may be selected from YbF₃, ScF₃, ScO₃,Y₂O₃, Ce₂O₃, GdF₃, and TbF₃. According to an exemplary embodiment of thepresent invention, the rare-earth metal compound may be selected fromYbF₃, ScF₃, TbF₃, YbI₃, ScI₃, and TbI₃; however, exemplary embodimentsof the present invention are not limited thereto.

The alkali metal complex, the alkaline earth-metal complex, and therare-earth metal complex may each include an ion of an alkali metal, analkaline earth-metal, or a rare-earth metal. A ligand coordinated with ametal ion of the alkali metal complex, the alkaline earth-metal complex,or the rare-earth metal complex may be independently selected from ahydroxyquinoline, a hydroxyisoquinoline, a hydroxybenzoquinoline, ahydroxyacridine, a hydroxyphenanthridine, a hydroxyphenyl oxazole, ahydroxyphenyl thiazole, a hydroxydiphenyl oxadiazole, a hydroxydiphenylthiadiazole, a hydroxyphenyl pyridine, a hydroxyphenyl benzimidazole, ahydroxyphenyl benzothiazole, a bipyridine, a phenanthroline, and acyclopentadiene; however exemplary embodiments of the present inventionare not limited thereto.

The electron injection layer may include an alkali metal, an alkalineearth-metal, a rare-earth metal, an alkali metal compound, an alkalineearth-metal compound, a rare-earth metal compound, an alkali metalcomplex, an alkaline earth-metal complex, a rare-earth metal complex, orany combination thereof. According to an exemplary embodiment of thepresent invention, the electron injection layer may include an organicmaterial. When the electron injection layer includes an organicmaterial, the alkali metal, the alkaline earth metal, therare-earth-metal, the alkali metal compound, the alkaline earth-metalcompound, the rare-earth metal compound, the alkali metal complex, thealkaline earth-metal complex, the rare-earth metal complex, or anycombination thereof may be substantially homogeneously ornon-homogeneously dispersed in a matrix including the organic material.

The thickness of the electron injection layer may be in a range fromabout 1 Å to about 100 Å, for example, from about 3 Å to about 90 Å.When the thickness of the electron injection layer is within any ofthese ranges, increased electron injection characteristics may beobtained without a substantial increase in driving voltage.

The second electrode 190 may be disposed on the organic layer 150. Theorganic layer 150 may have a structure as described above. The secondelectrode 190 may be a cathode. The cathode may be an electron injectionelectrode. A material included in the second electrode 190 may be amaterial with a relatively low work function, for example, a metal, analloy, an electrically conductive compound, or any combination thereof.

The second electrode 190 may include at least one of lithium (Li),silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li),calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), indiumtin oxide (ITO), or indium zinc oxide (IZO); however, exemplaryembodiments of the present invention are not limited thereto. The secondelectrode 190 may be a transmissive electrode, a semi-transmissiveelectrode, or a reflective electrode.

The second electrode 190 may have a single-layer structure.Alternatively, the second electrode 190 may have a multi-layer structureincluding two or more layers.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear orbranched saturated aliphatic hydrocarbon monovalent group having 1 to 60carbon atoms. Non-limiting examples thereof may include a methyl group,an ethyl group, a propyl group, an isobutyl group, a sec-butyl group, atert-butyl group, a pentyl group, an iso-amyl group, or a hexyl group.The term “C₁-C₆₀ alkylene group” as used herein refers to a divalentgroup having substantially the same structure as the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbongroup having at least one carbon-carbon double bond in the middle or atthe terminus of the C₂-C₆₀ alkyl group. Non-limiting examples thereofmay include an ethenyl group, a propenyl group, or a butenyl group. Theterm “C₂-C₆₀ alkenylene group” as used herein refers to a divalent grouphaving substantially the same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbongroup having at least one carbon-carbon triple bond in the middle or atthe terminus of the C₂-C₆₀ alkyl group. Non-limiting examples thereofmay include an ethynyl group and a propynyl group. The term “C₂-C₆₀alkynylene group” as used herein refers to a divalent group havingsubstantially the same structure as the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalentgroup represented by —OA₁₀₁, in which A₁₀₁ is the C₁-C₆₀ alkyl group.Non-limiting examples thereof may include a methoxy group, an ethoxygroup, or an isopropyloxy group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalentsaturated hydrocarbon monocyclic group having 3 to 10 carbon atoms.Non-limiting examples thereof may include a cyclopropyl group, acyclobutyl group, a cyclopentyl group, a cyclohexyl group, or acycloheptyl group. The term “C₃-C₁₀ cycloalkylene group” as used hereinrefers to a divalent group having substantially the same structure asthe C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to amonovalent monocyclic group including at least one heteroatom selectedfrom N, O, Si, P, and S as a ring-forming atom and 1 to 10 carbon atoms.Non-limiting examples thereof may include a 1,2,3,4-oxatriazolidinylgroup, a tetrahydrofuranyl group, or a tetrahydrothiophenyl group. Theterm “C₁-C₁₀ heterocycloalkylene group” as used herein refers to adivalent group having substantially the same structure as the C₁-C₁₀heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to amonovalent monocyclic group that has 3 to 10 carbon atoms and at leastone carbon-carbon double bond in its ring and is not aromatic.Non-limiting examples thereof may include a cyclopentenyl group, acyclohexenyl group, or a cycloheptenyl group. The term “C₃-C₁₀cycloalkenylene group” as used herein refers to a divalent group havingsubstantially the same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to amonovalent monocyclic group that has at least one heteroatom selectedfrom N, O, Si, P, and S as a ring-forming atom, 1 to 10 carbon atoms,and at least one carbon-carbon double bond in its ring. Non-limitingexamples of the C₁-C₁₀ heterocycloalkenyl group may include a4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, or a2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylenegroup” as used herein refers to a divalent group having substantiallythe same structure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent grouphaving a carbocyclic aromatic system having 60 to 60 carbon atoms. Theterm “C₆-C₆₀ arylene group” as used herein refers to a divalent grouphaving a carbocyclic aromatic system having 60 to 60 carbon atoms.Non-limiting examples of the C₆-C₆₀ aryl group may include a phenylgroup, a naphthyl group, an anthracenyl group, a phenanthrenyl group, apyrenyl group, or a chrysenyl group. When the C₆-C₆₀ aryl group and theC₆-C₆₀ arylene group each include two or more rings, the rings may bechemically bonded.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalentgroup having a heterocyclic aromatic system that has at least oneheteroatom selected from N, O, Si, P, and S as a ring-forming atom, inaddition to 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group”as used herein refers to a divalent group having a heterocyclic aromaticsystem that has at least one heteroatom selected from N, O, P, Si, and Sas a ring-forming atom, in addition to 1 to 60 carbon atoms.Non-limiting examples of the C₁-C₆₀ heteroaryl group may include apyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, or an isoquinolinyl group.When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group eachinclude two or more rings, the rings may be chemically bonded.

The term “C₆-C₆₀ aryloxy group” as used herein refers to —OA₁₀₂, inwhich A₁₀₂ is a C₆-C₆₀ aryl group. The term “C₆-C₆₀ arylthio group” asused herein refers to —SA₁₀₃, in which A₁₀₃ is a C₆-C₆₀ aryl group.

The term “monovalent non-aromatic condensed polycyclic group” as usedherein refers to a monovalent group that has two or more rings condensedand only carbon atoms (e.g., 8 to 60 carbon atoms) as ring-formingatoms, wherein the entire molecular structure is non-aromatic.Non-limiting examples of the monovalent non-aromatic condensedpolycyclic group may include a fluorenyl group. The term “divalentnon-aromatic condensed polycyclic group” as used herein refers to adivalent group having substantially the same structure as the monovalentnon-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” asused herein refers to a monovalent group that has two or more ringscondensed, at least one heteroatom selected from N, O, Si, P, and S, inaddition to carbon atoms (e.g., 1 to 60 carbon atoms), as ring-formingatoms, wherein the entire molecular structure is non-aromatic.Non-limiting examples of the monovalent non-aromatic condensedheteropolycyclic group may include a carbazolyl group. The term“divalent non-aromatic condensed heteropolycyclic group” as used hereinrefers to a divalent group having substantially the same structure asthe monovalent non-aromatic condensed heteropolycyclic group.

The term “C₅-C₆₀ carbocyclic group” as used herein refers to amonocyclic or polycyclic group having 5 to 60 carbon atoms as the onlyring-forming atoms. The C₅-C₆₀ carbocyclic group may be an aromaticcarbocyclic group or a non-aromatic carbocyclic group. The term “C₅-C₆₀carbocyclic group” may be a ring, such as a benzene, a monovalent group,such as a phenyl group, or a divalent group, such as a phenylene group.According to one or more exemplary embodiments of the present invention,depending on the number of substituents connected to the C₅-C₆₀carbocyclic group, the C₅-C₆₀ carbocyclic group may be a trivalent groupor a quadrivalent group.

The term “C₁-C₆₀ heterocyclic group” as used herein refers to a grouphaving substantially the same structure as the C₁-C₆₀ carbocyclic group,except that as a ring-forming atom, at least one heteroatom selectedfrom N, O, Si, P, and S may be used in addition to carbon atoms (e.g., 1to 60 carbon atoms).

At least one of substituents of the substituted C₅-C₆₀ carbocyclicgroup, substituted C₁-C₆₀ heterocyclic group, substituted C₃-C₁₀cycloalkylene group, substituted C₁-C₁₀ heterocycloalkylene group,substituted C₃-C₁₀ cycloalkenylene group, substituted C₁-C₁₀heterocycloalkenylene group, substituted C₆-C₆₀ arylene group,substituted C₁-C₆₀ heteroarylene group, substituted divalentnon-aromatic condensed polycyclic group, substituted divalentnon-aromatic condensed heteropolycyclic group, substituted C₁-C₆₀ alkylgroup, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynylgroup, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkylgroup, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group,substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxy group,substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀ heteroaryl group,substituted monovalent non-aromatic condensed polycyclic group, orsubstituted monovalent non-aromatic condensed heteropolycyclic group maybe selected from:

-   -   deuterium (-D), —F, —Cl, —Br, —I, a hydroxyl group, a cyano        group, a nitro group, an amidino group, a hydrazino group, a        hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a        C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;    -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl        group, and a C₁-C₆₀ alkoxy group, each substituted with at least        one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,        a cyano group, a nitro group, an amidino group, a hydrazino        group, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀        heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀        heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy        group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a        monovalent non-aromatic condensed polycyclic group, a monovalent        non-aromatic condensed heteropolycyclic group,        —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁),        —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);    -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a        C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a        C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio        group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic        condensed polycyclic group, and a monovalent non-aromatic        condensed heteropolycyclic group;    -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a        C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a        C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio        group, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic        condensed polycyclic group, and a monovalent non-aromatic        condensed heteropolycyclic group, each substituted with at least        one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,        a cyano group, a nitro group, an amidino group, a hydrazino        group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl        group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀        cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀        cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀        aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a        C₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed        polycyclic group, a monovalent non-aromatic condensed        heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂),        —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂);        and    -   —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),        —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).

Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independently beselected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroarylgroup, a monovalent non-aromatic condensed polycyclic group, amonovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group.

The term “Ph” as used herein represents a phenyl group. The term “Me” asused herein represents a methyl group. The term “Et” as used hereinrepresents an ethyl group. The term “ter-Bu” or “Bu^(t)” as used hereinrepresents a tert-butyl group. The term “OMe” as used herein representsa methoxy group.

The term “biphenyl group” as used herein refers to a phenyl groupsubstituted with a phenyl group. The “biphenyl group” may be asubstituted phenyl group having a C₆-C₆₀ aryl group as a substituent.

The term “terphenyl group” as used herein refers to a phenyl groupsubstituted with a biphenyl group. The “terphenyl group” may be asubstituted phenyl group having a C₆-C₆₀ aryl group substituted with aC₆-C₆₀ aryl group as a substituent.

The symbols * and *′ as used herein, unless defined otherwise, refer toa binding site to an adjacent atom in a corresponding formula.

A compound according to one or more exemplary embodiments of the presentinvention and an organic light-emitting device according to one or moreexemplary embodiments of the present invention will be described in moredetail below with reference to Synthesis Examples and Examples. However,exemplary embodiments of the present invention are not limited thereto.The expression “B was used instead of A” used in describing SynthesisExamples refers to an example in which a molar equivalent of A was thesame as a molar equivalent of B.

Example 1

As an anode, an ITO glass substrate was cut to a size of about 50 mm×50mm×0.5 mm, sonicated in isopropyl alcohol and pure water for about 15minutes in each solvent, cleaned with ultraviolet rays for about 30minutes, and then ozone, and mounted on a vacuum deposition apparatus.

m-MTDATA was vacuum-deposited on the ITO anode at a deposition rate ofabout 1 Å/sec to form a hole injection layer having a thickness of about800 Å, and α-NPD was vacuum-deposited on the hole injection layer at adeposition rate of about 1 Å/sec to form a hole transport layer having athickness of about 400 Å.

Compound 1-1 as a first host, Compound 2-1 as a second host, and a reddopant were vacuum-deposited on the hole transport region at adeposition rate of about 0.30 Å/sec, about 1 Å/sec, and about 0.10Å/sec, respectively, to form an emission layer having a thickness ofabout 400 Å.

Alq₃ was deposited on the emission layer to form an electron transportlayer having a thickness of about 300 Å, LiF was deposited on theelectron transport layer to form an electron injection layer having athickness of about 10 Å, and Al was vacuum-deposited on the electroninjection layer to form a cathode having a thickness of about 2,000 Å.Thus, an organic light-emitting device was formed.

Examples 2 to 10 and Comparative Examples 1 to 3

Organic light-emitting devices were manufactured in substantially thesame manner as in Example 1, except that compounds shown in Table 1 wereused as a first host and as a second host to form an emission layer.

Evaluation Example 1

The driving voltage and efficiency data of the organic light-emittingdevices manufactured in Examples 1 to 10 and Comparative Examples 1 to 3were measured by using a Keithley 236 source-measure unit (SMU) and aPR650 luminance meter. The results thereof are shown in Table 1.

TABLE 1 Ratio (first Driving Second host:second voltage Efficiency Firsthost host host:dopant) (V @5 mA/cm³) (cd/A) Example 1 1-1 2-1  3:7:1 5.418 Example 2 1-1 2-1  5:5:1 5.7 15 Example 3  1-14 2-1  3:7:1 5.8 17Example 4 1-1 2-35 3:7:1 5.9 20 Example 5  1-14 2-48 3:7:1 5.8 19Example 6 1-1 2-63 5:5:1 5.1 22 Example 7  1-14 2-63 5:5:1 5.0 23Example 8 1-1 2-65 5:5:1 5.2 21 Example 9 1-1 2-72 5:5:1 5.1 25 Example10  1-19 2-72 5:5:1 5.0 21 Comparative Comparative 2-4  5:5:1 8.1 9Example 1 Compound 1 Comparative Comparative — 1:0:1 11.5 4 Example 2Compound 2 Comparative Comparative Comparative 5:5:1 6.6 11 Example 3Compound 3 Compound 4

TABLE 2 First host Second host Comparative Example 1

Comparative Example 2

— Comparative Example 3

Referring to Table 1, the organic light-emitting devices of Examples 1to 10 had relatively high efficiency and lifespan characteristics, ascompared with the organic light-emitting devices of Comparative Examples1 to 3.

According to one or more exemplary embodiments of the present invention,an organic light-emitting device may have relatively high efficiency anda relatively long lifespan.

It should be understood that exemplary embodiments of the presentinvention described herein should be considered in a descriptive senseonly and not for purposes of limitation. Descriptions of features oraspects within each embodiment should typically be considered asavailable for other similar features or aspects in other exemplaryembodiments of the present invention.

While one or more exemplary embodiments of the present invention havebeen described with reference to the figures, it will be understood bythose of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention.

What is claimed is:
 1. An organic light-emitting device, comprising: afirst electrode; a second electrode facing the first electrode; and anorganic layer disposed between the first electrode and the secondelectrode, the organic layer comprising an emission layer, wherein theorganic layer comprises a first compound represented by Formula 1 and asecond compound represented by one of Formulae 2A to 2C:

wherein, in Formulae 1 and 2A to 2C: X₁ is selected from C(R₄)(R₅) andSi(R₄)(R₅), and R₄ and R₅ are linked to form a ring, X₂ is selected fromO, S, C(Z₂₁)(Z₂₂), N(Z₂₃), and Si(Z₂₄)(Z₂₅), Z₂₁ to Z₂₅ are eachindependently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, aquinolinyl group, an isoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a carbazolyl group, a triazinyl group,—Si(Q₄₁)(Q₄₂)(Q₄₃), —N(Q₄₁)(Q₄₂), —B(Q₄₁)(Q₄₂), —C(═O)(Q₄₁),—S(═O)₂(Q₄₁), and —P(═O)(Q₄₁)(Q₄₂), L₁, L₁₁, L₁₂, L₂₁ to L₂₃, and L₃₁ toL₃₅ are each independently selected from a substituted or unsubstitutedC₃-C₁₀ cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group, a1, a11, a12, a21 to a23,and a31 to a35 are each independently selected from 0 to 5; when a1 is 2or greater, at least two L₁(s) are the same as or different from eachother; when a11 is 2 or greater, at least two L₁₁(s) are the same as ordifferent from each other; when a12 is 2 or greater, at least two L₁₂(s)are the same as or different from each other; when a21 is 2 or greater,at least two L₂₁(s) are the same as or different from each other; whena22 is 2 or greater, at least two L₂₂(s) are the same as or differentfrom each other; when a23 is 2 or greater, at least two L₂₃(s) are thesame as or different from each other; when a31 is 2 or greater, at leasttwo L₃₁(s) are the same as or different from each other; when a32 is 2or greater, at least two L₃₂(s) are the same as or different from eachother; when a33 is 2 or greater, at least two L₃₃(s) are the same as ordifferent from each other; when a34 is 2 or greater, at least two L₃₄(s)are the same as or different from each other; and when a35 is 2 orgreater, at least two L₃₅(s) are the same as or different from eachother, A₁ is selected from P(═O)(R₄₁)(R₄₂) and S(═O)₂(R₄₃), b1 is aninteger selected from 1 to 5; when b1 is 2 or greater, at least twoA₁(s) are the same as or different from each other, Ar₁₁ is selectedfrom a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₁-C₆₀heteroaryl group, a substituted or unsubstituted monovalent non-aromaticcondensed polycyclic group, and a substituted or unsubstitutedmonovalent non-aromatic condensed heteropolycyclic group, b11 is aninteger selected from 1 to 5; when b11 is 2 or greater, at least twoAr₁₁(s) are the same as or different from each other, R₁ to R₅, R₁₁ toR₁₄, R₂₁ to R₂₃, R₃₁ to R₃₄, and R₄₁ to R₄₃ are each independentlyselected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, a substituted or unsubstituted C₁-C₆₀ alkylgroup, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂),—B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂), c1 and c11 toc14 are each independently an integer selected from 0 to 4; when c1 is 2or greater, at least two R₁(s) are the same as or different from eachother; when c11 is 2 or greater, at least two R₁₁(s) are the same as ordifferent from each other; when c12 is 2 or greater, at least two R₁₂(s)are the same as or different from each other; when c13 is 2 or greater,at least two R₁₃(s) are the same as or different from each other; andwhen c14 is 2 or greater, at least two R₁₄(s) are the same as ordifferent from each other, c2 is selected from 0 to 3; when c2 is 2 orgreater, at least two of R₂(s) are the same as or different from eachother, c3 is selected from 0 to 2; when c3 is 2 or greater, at least twoR₃(s) are the same as or different from each other, c21 to c23 and c31to c34 are each independently an integer selected from 1 to 5; when c21is 2 or greater, at least two R₂₁(s) are the same as or different fromeach other; when c22 is 2 or greater, at least two R₂₂(s) are the sameas or different from each other; when c23 is 2 or greater, at least twoR₂₃(s) are the same as or different from each other; when c31 is 2 orgreater, at least two R₃₁(s) are the same as or different from eachother; when c32 is 2 or greater, at least two R₃₂(s) are the same as ordifferent from each other; when c33 is 2 or greater, at least two R₃₃(s)are the same as or different from each other; and when c34 is 2 orgreater, at least two R₃₄(s) are the same as or different from eachother, and at least one of substituents of the substituted C₃-C₁₀cycloalkylene group, the substituted C₁-C₁₀ heterocycloalkylene group,the substituted C₃-C₁₀ cycloalkenylene group, substituted C₁-C₁₀heterocycloalkenylene group, the substituted C₆-C₆₀ arylene group,substituted C₁-C₆₀ heteroarylene group, the substituted divalentnon-aromatic condensed polycyclic group, the divalent non-aromaticcondensed heteropolycyclic group, substituted C₁-C₆₀ alkyl group, thesubstituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynyl group, thesubstituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₁-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, substituted C₁-C₆₀heteroaryl group, the substituted monovalent non-aromatic condensedpolycyclic group, and the substituted monovalent non-aromatic condensedheteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃),—N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(O)(Q₁₁), —S(═O)₂(Q₁₁), and—P(═O)(Q₁₁)(Q₁₂); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₁-C₆₀ heteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group, abiphenyl group, and a terphenyl group; a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, a biphenyl group, and a terphenylgroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, aC₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, a terphenyl group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂),—B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂); and—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(O₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), wherein Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ toQ₂₃, Q₃₁ to Q₃₃, and Q₄₁ to Q₄₃ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, aC₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroarylgroup, a monovalent non-aromatic condensed polycyclic group, amonovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group.
 2. The organic light-emitting device ofclaim 1, wherein L₁, L₁₁, L₁₂, L₂₁ to L₂₃, and L₃₁ to L₃₅ are eachindependently selected from: a phenylene group, a pentalenylene group,an indenylene group, a naphthylene group, an azulenylene group, aheptalenylene group, an indacenylene group, an acenaphthylene group, afluorenylene group, a spiro-bifluorenylene group, a benzofluorenylenegroup, a dibenzofluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, a pentaphenylene group, a hexacenylene group, a pentacenylenegroup, a rubicenylene group, a coronenylene group, an ovalenylene group,a pyrrolylene group, a thiophenylene group, a furanylene group, animidazolylene group, a pyrazolylene group, a thiazolylene group, anisothiazolylene group, an oxazolylene group, an isoxazolylene group, apyridinylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, an isoindolylene group, an indolylene group, anindazolylene group, a purinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a carbazolylene group, aphenanthridinylene group, an acridinylene group, a phenanthrolinylenegroup, a phenazinylene group, a benzimidazolylene group, abenzofuranylene group, a benzothiophenylene group, anisobenzothiazolylene group, a benzoxazolylene group, anisobenzoxazolylene group, a triazolylene group, a tetrazolylene group,an oxadiazolylene group, a triazinylene group, a dibenzofuranylenegroup, a dibenzothiophenylene group, a dibenzosilolylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, athiadiazolylene group, an imidazopyridinylene group, and animidazopyrimidinylene group; and a phenylene group, a pentalenylenegroup, an indenylene group, a naphthylene group, an azulenylene group, aheptalenylene group, an indacenylene group, an acenaphthylene group, afluorenylene group, a spiro-bifluorenylene group, a benzofluorenylenegroup, a dibenzofluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, a pentaphenylene group, a hexacenylene group, a pentacenylenegroup, a rubicenylene group, a coronenylene group, an ovalenylene group,a pyrrolylene group, a thiophenylene group, a furanylene group, animidazolylene group, a pyrazolylene group, a thiazolylene group, anisothiazolylene group, an oxazolylene group, an isoxazolylene group, apyridinylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, an isoindolylene group, an indolylene group, anindazolylene group, a purinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a carbazolylene group, aphenanthridinylene group, an acridinylene group, a phenanthrolinylenegroup, a phenazinylene group, a benzimidazolylene group, abenzofuranylene group, a benzothiophenylene group, anisobenzothiazolylene group, a benzoxazolylene group, anisobenzoxazolylene group, a triazolylene group, a tetrazolylene group,an oxadiazolylene group, a triazinylene group, a dibenzofuranylenegroup, a dibenzothiophenylene group, a dibenzosilolylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, athiadiazolylene group, an imidazopyridinylene group, and animidazopyrimidinylene group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, acyclohexyl group, a cycloheptyl group, a cyclopentenyl group, acyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group,a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, adibenzosilolylene group, a benzocarbazolyl group, a dibenzocarbazolylgroup, a thiadiazolyl group, an imidazopyridinyl group, animidazopyrimidinyl group, Si(Q₃₁)(Q₃₂)(Q₃₃), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁),and —P(═O)(Q₃₁)(Q₃₂), wherein Q₃₁ to Q₃₃ are each independently selectedfrom a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, and a naphthyl group.
 3. The organiclight-emitting device of claim 1, wherein L₁, L₁₁, L₁₂, L₂₁ to L₂₃, andL₃₁ to L₃₅ are each independently selected from groups represented byFormulae 3-1 to 3-42:

wherein, in Formulae 3-1 to 3-42, Y₁ is selected from O, S, C(Z₃)(Z₄),N(Z₅), or Si(Z₆)(Z₇), Z₁ to Z₇ are each independently selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, achrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group,a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, atriazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), wherein Q₃₁ to Q₃₃ areeach independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxygroup, a phenyl group, a biphenyl group, a terphenyl group, and anaphthyl group, d2 is an integer selected from 1 or 2, d3 is an integerselected from 1 to 3, d4 is an integer selected from 1 to 4, d5 is aninteger selected from 1 to 5, d6 is an integer selected from 1 to 6, d8is an integer selected from 1 to 8, and * and *′ each indicate a bindingsite to an adjacent atom.
 4. The organic light-emitting device of claim1, wherein in Formula 1, L₁ is selected from: a phenylene group, anaphthylene group, a fluorenylene group, a benzofluorenylene group, aphenanthrenylene group, an anthracenylene group, a pyrenylene group, anda chrysenylene group; and a phenylene group, a naphthylene group, afluorenylene group, a benzofluorenylene group, a phenanthrenylene group,an anthracenylene group, a pyrenylene group, and a chrysenylene group,each substituted with at least one selected from deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), wherein Q₃₁ to Q₃₃ areeach independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxygroup, a phenyl group, a biphenyl group, a terphenyl group, and anaphthyl group.
 5. The organic light-emitting device of claim 1, whereinin Formula 2a, L₁₁ and L₁₂ are each independently selected from: aphenylene group, a naphthylene group, a fluorenylene group, abenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a pyrenylene group, and a chrysenylene group; and a phenylenegroup, a naphthylene group, a fluorenylene group, a benzofluorenylenegroup, a phenanthrenylene group, an anthracenylene group, a pyrenylenegroup, and a chrysenylene group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and—P(═O)(Q₃₁)(Q₃₂), wherein Q₃₁ to Q₃₃ are each independently selectedfrom a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, and a naphthyl group, and L₂₁ to L₂₃and L₃₁ to L₃₅ are each independently selected from: a phenylene group,a naphthylene group, a fluorenylene group, a spiro-bifluorenylene group,a benzofluorenylene group, a dibenzofluorenylene group, aphenanthrenylene group, an anthracenylene group, a pyrenylene group, achrysenylene group, a pyridinylene group, a pyrazinylene group, apyrimidinylene group, a pyridazinylene group, a quinolinylene group, anisoquinolinylene group, a quinoxalinylene group, a quinazolinylenegroup, a carbazolylene group, and a triazinylene group; and a phenylenegroup, a naphthylene group, a fluorenylene group, a spiro-bifluorenylenegroup, a benzofluorenylene group, a dibenzofluorenylene group, aphenanthrenylene group, an anthracenylene group, a pyrenylene group, achrysenylene group, a pyridinylene group, a pyrazinylene group, apyrimidinylene group, a pyridazinylene group, a quinolinylene group, anisoquinolinylene group, a quinoxalinylene group, a quinazolinylenegroup, a carbazolylene group, a triazinylene group, —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and—P(═O)(Q₃₁)(Q₃₂), each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, achrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, a quinolinyl group, anisoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acarbazolyl group, and a triazinyl group.
 6. The organic light-emittingdevice of claim 1, wherein in Formula 1, a1 is an integer selected from1 to
 3. 7. The organic light-emitting device of claim 1, wherein inFormulae 2A to 2C, a11 is an integer selected from 0 or 1, a12 is 0, a21to a23 and a31 to a34 are each independently integers selected from 0 to4, and a35 is an integer selected from 2 to
 4. 8. The organiclight-emitting device of claim 1, wherein Ar₁₁ is selected from: aphenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, a heptalenylgroup, an indacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenalenyl group, a phenanthrenyl group, an anthracenyl group,a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, achrysenyl group, a naphthacenyl group, a picenyl group, a perylenylgroup, a pentaphenyl group, a hexacenyl group, a pentacenyl group, arubicenyl group, a coronenyl group, an ovalenyl group, a pyrrolyl group,a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, an isoindolyl group, an indolyl group, anindazolyl group, a purinyl group, a quinolinyl group, an isoquinolinylgroup, a benzoquinolinyl group, a phthalazinyl group, a naphthyridinylgroup, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, acarbazolyl group, a phenanthridinyl group, an acridinyl group, aphenanthrolinyl group, a phenazinyl group, a benzimidazolyl group, abenzofuranyl group, a dibenzofuranyl group, a benzothiophenyl group, adibenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an oxadiazolyl group, a triazinyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a thiadiazolyl group, an imidazopyridinylgroup, an imidazopyrimidinyl group, a naphthoxanthenyl group, adibenzosilolyl group, a benzonaphthofuranyl group, and a benzopyrenylgroup; and a phenyl group, a biphenyl group, a terphenyl group, apentalenyl group, an indenyl group, a naphthyl group, an azulenyl group,a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a dibenzofuranyl group, abenzothiophenyl group, a dibenzothiophenyl group, an isobenzothiazolylgroup, a benzoxazolyl group, an isobenzoxazolyl group, a triazolylgroup, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, abenzocarbazolyl group, a dibenzocarbazolyl group, a thiadiazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, anaphthoxanthenyl group, a dibenzosilolyl group, a benzonaphthofuranylgroup, and a benzopyrenyl group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group,a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, acyclohexenyl group, a phenyl group, a biphenyl group, a terphenyl group,a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, apyrrolyl group, a thiophenyl group, a furanyl group, an imidazolylgroup, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, anoxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinylgroup, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, anindolyl group, an indazolyl group, a purinyl group, a quinolinyl group,an isoquinolinyl group, a benzoquinolinyl group, a phthalazinyl group, anaphthyridinyl group, a quinoxalinyl group, a quinazolinyl group, acinnolinyl group, a carbazolyl group, a phenanthridinyl group, anacridinyl group, a phenanthrolinyl group, a phenazinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinylgroup, a dibenzofuranyl group, a dibenzothiophenyl group, adibenzosilolyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, a thiadiazolyl group, an imidazopyridinyl group, animidazopyrimidinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), whereinQ₃₁ to Q₃₃ are each independently selected from a C₁-C₁₀ alkyl group, aC₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.
 9. The organic light-emitting device ofclaim 1, wherein Ar₁₁ is selected from: a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, a fluorenyl group, ananthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinylgroup, a dibenzofuranyl group, and a dibenzothiophenyl group; a phenylgroup, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, an anthracenyl group, a pyrenyl group, a chrysenylgroup, a pyridinyl group, a dibenzofuranyl group, and adibenzothiophenyl group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and—P(═O)(Q₃₁)(Q₃₂), wherein Q₃₁ to Q₃₃ are each independently selectedfrom a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, and a naphthyl group.
 10. The organiclight-emitting device of claim 1, wherein R₁ to R₅, R₁₁ to R₁₄, R₂₁ toR₂₃, R₃₁ to R₃₄, and R₄₁ to R₄₃ are each independently selected from:hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group; a phenylgroup, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolylgroup, a thiophenyl group, a furanyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, apyrimidinyl group, a pyridazinyl group, a quinolinyl group, anisoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a benzimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, acarbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, adibenzosilolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group; a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolylgroup, a thiophenyl group, a furanyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, apyrimidinyl group, a pyridazinyl group, a quinolinyl group, anisoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a benzimidazolyl group, a benzofuranyl group, abenzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group,an isobenzoxazolyl group, an oxadiazolyl group, a triazinyl group, acarbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, adibenzosilolyl group, an imidazopyridinyl group, and animidazopyrimidinyl group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a triphenylenylgroup, a pyrenyl group, a chrysenyl group, a pyrrolyl group, athiophenyl group, a furanyl group, an imidazolyl group, a pyrazolylgroup, a thiazolyl group, an isothiazolyl group, an oxazolyl group, anisoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group,a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, abenzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, anisobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group,an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, adibenzothiophenyl group, a dibenzosilolyl group, an imidazopyridinylgroup, an imidazopyrimidinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂); and—Si(Q₁)(Q₂)(Q₃), —C(═O)(Q₁), —S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂), wherein Q₁to Q₃ and Q₃₁ to Q₃₃ are each independently selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.
 11. The organic light-emittingdevice of claim 1, wherein in Formula 1, X₁ is selected from C(R₄)(R₅)and Si(R₄)(R₅), R₄ and R₅ are chemically bonded to each other to form aring, A₁ is selected from P(═O)(R₄₁)(R₄₂) and S(═O)₂(R₄₃), and R₁ to R₅and R₄₁ to R₄₃ are each independently selected from: hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, a naphthyl group, an anthracenylgroup, a pyrenyl group, a chrysenyl group, and a pyridinyl group; aC₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, an anthracenyl group, apyrenyl group, a chrysenyl group, and a pyridinyl group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₁₀ alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a pyridinyl group, a pyrimidinyl group, a triazinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), and —Si(Q₁)(Q₂)(Q₃), —C(═O)(Q₁),—S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂), wherein Q₁ to Q₃ and Q₃₁ to Q₃₃ areeach independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxygroup, a phenyl group, a biphenyl group, a terphenyl group, and anaphthyl group.
 12. The organic light-emitting device of claim 1,wherein in Formulae 2A to 2C, R₁₁ to R₁₄ are each independently selectedfrom: hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group, ananthracenyl group, a pyrenyl group, a chrysenyl group, and a pyridinylgroup; a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, a naphthyl group, an anthracenylgroup, a pyrenyl group, a chrysenyl group, and a pyridinyl group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₁₀ alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a pyridinyl group, a pyrimidinyl group, a triazinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂); and —Si(Q₁)(Q₂)(Q₃), —C(═O)(Q₁),—S(═O)₂(Q₁), and —P(═O)(Q₁)(Q₂), wherein Q₁ to Q₃ and Q₃₁ to Q₃₃ areeach independently selected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxygroup, a phenyl group, a biphenyl group, a terphenyl group, and anaphthyl group, and R₂₁ to R₂₃ and R₃₁ to R₃₄ are each independentlyselected from: a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, aquinolinyl group, an isoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a carbazolyl group, a dibenzofuranyl group, adibenzothiophenyl group, a dibenzosilolyl group, and a triazinyl group;and a phenyl group, a biphenyl group, a terphenyl group, a naphthylgroup, a fluorenyl group, a spiro-bifluorenyl group, a benzofluorenylgroup, a dibenzofluorenyl group, a phenanthrenyl group, an anthracenylgroup, a pyrenyl group, a chrysenyl group, a pyridinyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a quinolinylgroup, an isoquinolinyl group, a quinoxalinyl group, a quinazolinylgroup, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a dibenzosilolyl group, and a triazinyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group, anazulenyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, aquinolinyl group, an isoquinolinyl group, a quinoxalinyl group, aquinazolinyl group, a carbazolyl group, a triazinyl group,—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).
 13. The organic light-emittingdevice of claim 1, wherein the first compound is represented by one ofFormulae 1-1 to 1-4, and the second compound is selected from compoundsrepresented by Formulae 2a-1 to 2a-4, 2b-1 to 2b-4, and 2c-1; compoundsrepresented by Formula 2b in which L₂₁ is selected from a fluorenylenegroup, a spiro-bifluorenylene group, a carbazolylene group, adibenzofuranylene group, and a dibenzothiophenylene group; compoundsrepresented by Formula 2b in which R₂₁ is selected from a fluorenylgroup, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranylgroup, and a dibenzothiophenyl group; and compounds represented byFormula 2b in which L₂₁ to L₂₃ are a phenylene group and R₂₁ to R₂₃ area phenyl group:

wherein, in Formulae 1-1 to 1-4, 2a-1 to 2a-4, 2b-1 to 2b-4, and 2c-1,L₁, L₁₁, L₂₁ to L₂₃, L₃₁ to L₃₄, a1, a11, a21 to a23, a31 to a35, Ar₁₁,b11, R₁ to R₅, R₁₁ to R₁₄, R₂₃, R₃₁ to R₃₄, R₄₁ to R₄₃, c1 to c3, c11 toc14, c23, c31 to c34, and X₂ are the same as in claim 1, X₃ and X₄ arethe same as X₂ as in claim 1, R₂₁₁ to R₂₁₈ and R₂₂₃ are the same as R₁₁to R₁₄ as in claim 1, c211, c214 to c218, and c223 are eachindependently integers selected from 0 to 4; when c211 is 2 or greater,at least two R₂₁₁(s) are the same as or different from each other; whenc214 is 2 or greater, at least two R₂₁₄(s) are the same as or differentfrom each other; when c215 is 2 or greater, at least two R₂₁₅(s) are thesame as or different from each other; when c216 is 2 or greater, atleast two R₂₁₆(s) are the same as or different from each other; whenc217 is 2 or greater, at least two R₂₁₇(s) are the same as or differentfrom each other; when c218 is 2 or greater, at least two R₂₁₈(s) are thesame as or different from each other; and when c223 is 2 or greater, atleast two R₂₂₃(s) are the same as or different from each other, and c212and c213 are each independently integers selected from 0 to 3; when c212is 2 or greater, at least two R₂₁₂(s) are the same as or different fromeach other; and when c213 is 2 or greater, at least two R₂₁₃(s) are thesame as or different from each other.
 14. The organic light-emittingdevice claim 13, wherein L₁ and L₁₁ are each independently selectedfrom: a phenylene group, a naphthylene group, a fluorenylene group, abenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a pyrenylene group, and a chrysenylene group; and a phenylenegroup, a naphthylene group, a fluorenylene group, a benzofluorenylenegroup, a phenanthrenylene group, an anthracenylene group, a pyrenylenegroup, and a chrysenylene group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and—P(═O)(Q₃₁)(Q₃₂), L₂₁ to L₂₃ and L₃₁ to L₃₄ are each independentlyselected from: a phenylene group, a naphthylene group, a fluorenylenegroup, a spiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a pyrenylene group, a chrysenylene group, a pyridinylene group, apyrazinylene group, a pyrimidinylene group, a pyridazinylene group, aquinolinylene group, an isoquinolinylene group, a quinoxalinylene group,a quinazolinylene group, a carbazolylene group, and a triazinylenegroup; and a phenylene group, a naphthylene group, a fluorenylene group,a spiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a pyrenylene group, a chrysenylene group, a pyridinylene group, apyrazinylene group, a pyrimidinylene group, a pyridazinylene group, aquinolinylene group, an isoquinolinylene group, a quinoxalinylene group,a quinazolinylene group, a carbazolylene group, and a triazinylenegroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a pyrenyl group, a chrysenyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anisoindolyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, atriazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), a1 is an integerselected from 1 to 3, a11 is an integer selected from 0 or 1, a21 to a23and a31 to a34 are each independently integers selected from 0 to 4, a35is an integer selected from 2 to 4, R₁ to R₅, R₁₁ to R₁₄, and R₄₁ to R₄₃are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, an anthracenyl group, a pyrenylgroup, a chrysenyl group, and a pyridinyl group; a C₁-C₁₀ alkyl group, aC₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, a naphthyl group, an anthracenyl group, a pyrenyl group, achrysenyl group, and a pyridinyl group, each substituted with at leastone selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, a naphthyl group, a pyridinyl group,a pyrimidinyl group, a triazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and—P(═O)(Q₃₁)(Q₃₂); and —Si(Q₁)(Q₂)(Q₃), —C(═O)(Q₁), —S(═O)₂(Q₁), and—P(═O)(Q₁)(Q₂), wherein Q₁ to Q₃ and Q₃₁ to Q₃₃ are each independentlyselected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenylgroup, a biphenyl group, a terphenyl group, and a naphthyl group, andR₂₁ to R₂₃ and R₃₁ to R₃₄ are each independently selected from: a phenylgroup, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, apyrenyl group, a chrysenyl group, a pyridinyl group, a pyrazinyl group,a pyrimidinyl group, a pyridazinyl group, a quinolinyl group, anisoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, acarbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, adibenzosilolyl group, and a triazinyl group; and a phenyl group, abiphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group,a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, achrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group,a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group,and a triazinyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, an azulenyl group, a fluorenyl group,a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, achrysenyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinylgroup, a pyridazinyl group, a quinolinyl group, an isoquinolinyl group,a quinoxalinyl group, a quinazolinyl group, a carbazolyl group, atriazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).
 15. The organiclight-emitting device claim 13, wherein L₁ and L₁₁ are eachindependently selected from: a phenylene group, a naphthylene group, aphenanthrenylene group, an anthracenylene group, a pyrenylene group, anda chrysenylene group; and a phenylene group, a naphthylene group, aphenanthrenylene group, an anthracenylene group, a pyrenylene group, anda chrysenylene group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂), L₂₁ toL₂₃ and L₃₁ to L₃₄ are each independently selected from: a phenylenegroup, a naphthylene group, a fluorenylene group, a spiro-bifluorenylenegroup, a benzofluorenylene group, a dibenzofluorenylene group, aphenanthrenylene group, an anthracenylene group, a pyrenylene group, achrysenylene group, a carbazolylene group, and a triazinylene group; anda phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a pyrenylene group, a chrysenylene group, a carbazolylene group,and a triazinylene group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and—P(═O)(Q₃₁)(Q₃₂), a1 is an integer selected from 1 to 3, a11 is aninteger selected from 0 or 1, a21 to a23 and a31 to a34 are eachindependently integers selected from 0 to 4, a35 is an integer selectedfrom 2 to 4, R₁ to R₅, R₁₁ to R₁₄, and R₄₁ to R₄₃ are each independentlyselected from: hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxygroup, a phenyl group, a biphenyl group, a terphenyl group, a naphthylgroup, and an anthracenyl group; a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxygroup, a phenyl group, a biphenyl group, a terphenyl group, a naphthylgroup, and an anthracenyl group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amidino group, a hydrazino group, a hydrazonogroup, a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, a naphthyl group, a pyridinyl group,a pyrimidinyl group, a triazinyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and—P(═O)(Q₃₁)(Q₃₂); and —Si(Q₁)(Q₂)(Q₃), —C(═O)(Q₁), —S(═O)₂(Q₁), and—P(═O)(Q₁)(Q₂), wherein Q₁ to Q₃ and Q₃₁ to Q₃₃ are each independentlyselected from a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenylgroup, a biphenyl group, a terphenyl group, and a naphthyl group, andR₂₁ to R₂₃ and R₃₁ to R₃₄ are each independently selected from: a phenylgroup, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, apyrenyl group, a chrysenyl group, a pyridinyl group, a carbazolyl group,a dibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolylgroup, and a triazinyl group; and a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, achrysenyl group, a pyridinyl group, a carbazolyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a dibenzosilolyl group, and atriazinyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, an azulenyl group, a fluorenyl group,a spiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a pyrenyl group, achrysenyl group, a pyridinyl group, a carbazolyl group, a triazinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂).
 16. The organic light-emittingdevice of claim 1, wherein the first compound is selected from Compounds1-1 to 1-30, and the second compound is selected from Compounds 2-1 to2-74:


17. The organic light-emitting device of claim 1, wherein the firstelectrode is an anode, the second electrode is a cathode, and theorganic layer comprises a hole transport region disposed between thefirst electrode and the emission layer and an electron transport regiondisposed between the emission layer and the second electrode, whereinthe hole transport region comprises at least one selected from a holeinjection layer, a hole transport layer, a buffer layer, and an electronblocking layer, and the electron transport region comprises at least oneselected from a hole blocking layer, an electron transport layer, and anelectron injection layer.
 18. The organic light-emitting device of claim1, wherein the emission layer comprises the first compound and thesecond compound.
 19. The organic light-emitting device of claim 1,wherein the emission layer comprises a host and a dopant, and the hostcomprises the first compound and the second compound, wherein the amountof the host is greater than that of the dopant.
 20. The organiclight-emitting device of claim 19, wherein the dopant is selected fromorganometallic compounds comprising a heavy metal selected from iridium(Ir), platinum (Pt), osmium (Os), rhodium (Rh), tungsten (W), andpalladium (Pd).